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Numeric Data movement - to a COMP variableTable of contentsBackgroundSection 1: Re-looking at the BackgroundSection 2: Data storage in PIC S9(01) COMP thru PIC S9(09) COMP – Sample ProgramsSection 3: Observation of Data storage in PIC S9(01) COMP thru PIC S9(09) COMPSection 4: Conclusion on PIC S9(01) COMP thru PIC S9(09) COMPSection 5: Effect of ARITH(EXTEND)Section 6: Effect of TRUNC(BIN) or TRUNC(STD)Section 7: HEX ON analysisSection 8: What would happen if COMP variable had a fractional part?Section 9: Answered QuestionsSection 10: Practice QuestionsBackgroundHave you ever thought/checked/observed what would happen if we replaced a PIC S9(04) COMP variable that is used for computation with, say PIC S9(01) or PIC S9(02) COMP??Have you ever thought/checked/observed whether any other COMP variable can do same things that most commonly used COMP – viz. PIC S9(04) COMP - can do??Have you ever thought/checked/observed what would happen if in linkage section of a cobol program (that received data from jcl) if we coded length variable, not as PIC S9(04) COMP but as PIC S9(2) COMP or PIC S9(08) COMP or PIC 9(02) COMP etc, say??Have you ever thought/checked/observed if there is a significance as to why DB2 converts, during DCLGEN process, SMALLINT to PIC S9(04) COMP and INTEGER to PIC S9(09) COMP??Have you ever thought/checked/observed what maximum value PIC S9(0N) COMP (N = 1 thru 18) can hold in itself??Have you ever thought/checked/observed whether PIC S9(08) COMP, say, can only store up to 8 digits, or can it store more as well?Are you sure if PIC S9(N) COMP can only store up to N digits?Have you ever checked/observed differences between HEX values stored in a signed COMP vs an unsigned COMP?Have you ever checked/observed the behavior of a COMP field if it is declared with a decimal part?…..and so on. All these questions are focused around a numeric data type – USAGE COMPUTATIONAL or COMP, in short. Generally, COMP poses challenge for most of us. It is not primarily because it is difficult to understand it (as literature is available) but because it is not further looked or researched into. This research is extremely important to become more familiar with the subject. Literature normally caters well to the needs of what is generally observed, and, therefore, we tend to stick to what it provides. The below scenario that appeared triggered dwelling deeper into behavior of COMP fields.Project scenario: There was this file had a field that was defined as PIC S9(04) COMP. It received 4-digit values in it. A process consisting of a few jobs created this file. This file, in turn, served as input to a subsequent process.As part of change in requirement, it was expected that 5-digit numbers would start coming to the file variable. In the file PIC S9(04) COMP was getting changed. It was decided to change it to PIC S9(05).PIC S9(04) COMP --- PIC S9(05)Another team made changes to the programs executing in jobs that created this file.Our team needed to carry out impact analysis on the programs that read data from this file and proceed further.In one of the programs, numeric variables (defined in working-storage section as PIC S9(04) COMP) received and computed very well values that they got from this file variable. So, PIC S9(04) COMP on these working-storage variables was expected to be changed to PIC S9(05), to be able to process all 5-digit numbers. Design document was completed and handed over to developer. Developer made following 2 errors in coding.Variable1: it was changed from PIC S9(04) COMP - PIC S9(04). He just dropped the ‘COMP’ but did not change ‘04’ to ‘05’. Variable2: He did not make any change (overlooked to make the change). Naturally, errors were found during testing phase. Testing was carried out using many 5-digit numbers (as test cases). This led to analyzing data movement to COMP. Many study gates were open during this research and later on. A few compiler options came up for study in order to understand behavior of COMP fields.Caution: This document only discusses behavior of following types of numeric data types vis-à-vis compiler optionsCOMPDISPLAYCOMP-3So, please read through the document keeping this in mindThe document may appear lengthy, but information in it is categorized, to an extent, so as to help grasp it effectively. Any suggestions to make the document more concise are most welcome. Also, proof-reading has not been carried out deeply. So, some mistakes might have inadvertently crept. If you notice any, please inform.So, let us understand the COMP in greater detail.COBOL behaviour is deeply governed by how we compile it. And, this makes having knowledge of compilation parameters more important. Though on majority of times, they do not lead us to problems, knowledge of them can be handy, and can help solve many unwanted scenarios, which may be very difficult to solve without their knowledge, and we may spend days to search for reason. Two compiler parameters are also discussed while analyzing COMP - ARITH, TRUNCAlso, as you read on, associated with a data item keep these two important things in mind:Rule for size of Memory allotment to a data item – let us call it memory size allotment rule.Rule for what data this memory can accept – Let us call it data limit acceptance rule.These are two different rules. Many times we confuse memory and data to follow one rule. This is because of the misconception that we think memory location and its data storing capability have a single rule to follow. This is not true. There are 2 rules – one rule that governs size of memory allotted to a data item, and a second rule (a totally separate rule), that determines what can go inside this memory, and what cannot go inside this memory.It is like this. We may have a big room A that permits boxes of small and big sizes. Whereas another room B (of same size) may put a rule that only small boxes are permitted. Due to this restriction boxes of bigger size do not find entry into the second room B. Just to introduce, PIC S9(5) COMP. It occupies 4 bytes always. This is as per one rule (memory size allotment rule). But it can store 10 digit numbers in some scenario, whereas it can only store up to 5-digit numbers in another scenario. This difference in behavior is changed by changing the compiler settings to manipulate the data limit acceptance rule.IMPORTANT NOTE: For all programs compiled below, ARITH(COMPAT), TRUNC(BIN) compiler options were in effect. Wherever, compilation was performed using different option values, it is clearly stated. If you are confident on the topic of this discussion, you can skip the discussions that follow and go through practice questions given at the end to test your knowledge.Section 1: Re-looking at the BackgroundCase 1:01 WS-A PIC S9(11) VALUE 274 / 3867 / 38000 / 50000 / 123456 / 3245614 / 1357913579 / 24680246802.01 WS-B PIC S9(05).01 WS-C PIC S9(10).MOVE WS-A TO WS-BMOVE WS-A TO WS-CCase 2:01 WS-A PIC S9(11) VALUE 274 / 3867 / 38000 / 50000 / 123456 / 3245614 / / 1357913579 / 24680246802.01 WS-B PIC S9(04) COMP.01 WS-C PIC S9(09) COMP.MOVE WS-A TO WS-B MOVE WS-A TO WS-CWS-B, WS-C in Case1 are of USAGE DISPLAY.WS-B, WS-C in Case2 are of USAGE COMP.Here our task is to observe and compare outputs of Case1 and Case2.First of all, Why have we chosen to compare PIC S9(04) COMP vs PIC S9(05) and not PIC S9(04) COMP vs PIC S9(04)?PIC S9(09) COMP vs PIC S9(10) and not PIC S9(09) COMP vs PIC S9(09)?The reason is that PIC S9(04) COMP, even though seemingly shows to have 4 digits (apparently indicated by 9(04)) can actually store a few 5-digit numbers as well.Similarly, PIC S9(09) COMP, even though seemingly shows to have 9 digits (apparently indicated by 9(09)) can actually store a few 10-digit numbers as well.PIC S9(04) COMP –> is actually a 5-digit variable (storing some of 5-digit numbers)PIC S9(09) COMP –> is actually a 10-digit variable(storing some of 10-digit numbers)So, we are comparing 5-digit variable - PIC S9(05) - with another 5-digit variable - PIC S9(04) COMPAnd 10-digit variable - PIC S9(10) - with another 10-digit variable - PIC S9(09) COMP.So, this is fair comparison that we are doing.Revising Rules of Data movement to numeric variablesWe are fairly familiar with data movement to USAGE DISPLAY numeric fields – in this case to PIC S9(N) and to its variations involving SIGN clause. To restate, they follow following ruleDecimal alignment - of incoming data and the receiving field.Right justification before decimalLeft justification after decimalRevising data storage in numeric variablesLet’s take an example. Let’s give a quick glance at how +123 and -123 get stored in each of three normally used numeric data types – USAGE DISPLAY, USAGE COMP-3, USAGE COMPUSAGE DISPLAYUnsigned variablePIC 9(3) – 3 bytes+123Individual bits (actual storage)111100011111001011110011Understanding in HexadecimalF1F2F3Understanding in Decimal123Comments: Each digit occupies 8 bits. -123Cannot store it. PIC 9(3) only stores 0 and positive numbers.Signed variablePIC S9(3) – 3 bytes+123Individual bits (actual storage)111100011111001011000011Understanding in HexadecimalF1F2C3Understanding in Decimal12CComments: Each digit occupies 8 bits. Last (rightmost) digit (here ‘3’) is superimposed with sign of the number(here +ve). For positive numbers, ‘1’ is substituted by ‘A’, ‘2’ is substituted by ‘B’, ‘3’ is substituted by ‘C’, and so on. For negative numbers, ‘1’ is substituted by ‘J’, ‘2’ is substituted by ‘K’, ‘3’ is substituted by ‘L’, and so on.-123Individual bits (actual storage)111100011111001011010011Understanding in HexadecimalF1F2D3Understanding in Decimal12LComments: Each digit occupies 8 bits. Last (rightmost) digit (here ‘3’) is superimposed with sign of the number(here -ve). For positive numbers, ‘1’ is substituted by ‘A’, ‘2’ is substituted by ‘B’, ‘3’ is substituted by ‘C’, and so on. For negative numbers, ‘1’ is substituted by ‘J’, ‘2’ is substituted by ‘K’, ‘3’ is substituted by ‘L’, and so on.USAGE COMP-3Unsigned variablePIC 9(3) COMP-3 – 2 bytes+123Individual bits (actual storage)0001001000111111Understanding in Hexadecimal123FUnderstanding in Decimal123This is for storing sign(+ve)Comments: Each digit occupies 4 bits. 4 bits reserved for sign at right. Unsigned variable shows sign as hexadecimal ‘F’ on extreme right.-123Cannot store it. PIC 9(3) COMP-3 only stores 0 and positive numbers.Signed variablePIC S9(3) COMP-3 – 2 bytes+123Individual bits (actual storage)0001001000111100Understanding in Hexadecimal123CUnderstanding in Decimal123This is for storing sign(+ve)Comments: Each digit occupies 4 bits. Sign occupies 4 bits. Signed variable shows sign as hexadecimal ‘C’ for +ve on extreme right. Hexadecimal ‘D’ for –ve.-123Individual bits (actual storage)0001001000111101Understanding in Hexadecimal123DUnderstanding in Decimal123This is for storing sign(-ve)Comments: Each digit occupies 4 bits. Sign occupies 4 bits. Signed variable shows sign as hexadecimal ‘C’ for +ve on extreme right. Hexadecimal ‘D’ for –ve.USAGE COMPUnsigned variablePIC 9(3) COMP – 2 bytes+123Individual bits (actual storage)0000000001111011Understanding in Hexadecimal007BUnderstanding in Decimal123Comments: Number is converted to pure binary. Here, no specific set of bits represent ‘1’, ‘2’ or ‘3’. It is a single-piece 123.-123Cannot store it. PIC 9(3) COMP only stores 0 and positive numbers.Signed variablePIC S9(3) COMP – 2 bytes+123Individual bits (actual storage)0000000001111011Understanding in Hexadecimal007BUnderstanding in Decimal123Comments: Number is converted to pure binary. Here, no specific set of bits represent ‘1’, ‘2’ or ‘3’. It is a single- piece 123.-123Individual bits (actual storage)1111111110000101Understanding in HexadecimalFF85Understanding in Decimal65413Comments: An UNSIGNED 2-byte COMP variable has a range (0 thru +65535). A SIGNED 2-byte COMP variable has a range (-32,768 thru +32,767). Both variables occupy same memory size. When the variable is changed to SIGNED, system knows that a 2-byte signed COMP variable CANNOT store beyond +32767. So, what it does is it allots the range (+32768 thru +65535) to negative numbersExplanation for storing -123 in PIC S9(03) COMP16151413121110987654321 PIC 9(3) COMP16151413121110987654321 PIC S9(3) COMPNotice that the above 16-bit memory may, at one time, can get allotted to a PIC 9(3) COMP (unsigned variable), and, at another time, may get allocated to PIC S9(03) COMP (signed variable). How does it behave differently (as regards data storage) when ‘looked’ from two different data types?PIC 9(3) COMP: We are not interested in storing the sign here. We want to utilize all 16 bits for storing data purpose. As it is a 16-bit memory, the maximum decimal number that can get stored is when each of 16 bits stores in itself a binary ‘1’. So, we have sixteen 1‘s. This corresponds to a decimal number 65535 (2^16 – 1). So, a total of 65,536 decimal numbers can be stored (0 thru 65,535).PIC S9(3) COMP: We are interested in storing the sign here. We must allocate 1 bit for that (2 possibilities – one for storing +ve sign, and the other for storing –ve sign). Leftmost – 16th bit is reserved for sign. Therefore, we only have 15 remaining bits for storing data. In 15 bits, we can store (2^15 – 1 = 32767) numbers. Also, we can store 0. 0 corresponds to all 15 bits as ‘0’. 32,767 corresponds to all 15 bits as ‘1’. That means if we fix sign bit as ‘0’, say, then with it we have 32,768 positive numbers (0 thru 32,767). Similarly, if we fix sign bit as ‘1’, then with it we have another 32,768 numbers (these are -32,768 thru -1). So, total range is (-32,768 thru -1, 0, +1 thru +32,767). That means altogether we can store 65,536 numbers.How are negative numbers stored?Binary bit patternsWhich decimal number is represented via below??PIC 9(3) COMPPIC S9(3) COMP16th bit is '0'??0000 0000 0000 0000000000 0000 0000 0001110111 1111 1111 111032766327660111 1111 1111 1111327673276716th bit changes to '1'??1000 0000 0000 000032768-327681000 0000 0000 000132769-327671000 0000 0000 001032770-327661111 1111 1000 010165413-1231111 1111 1111 111065534-21111 1111 1111 111165535-1Memory storage is identical-sized for signed and unsigned COMP. When 16th bit is fixed as '0' then for any bit pattern they represent same decimal number. That means positive numbers are identically represented in binary bits by both PIC 9(3) COMP and by PIC S9(3) COMP. But when 16th bit changes to '1', then same bit pattern no longer represents same decimal number. When 16th bit is ‘1’, the number as a whole is understood as POSITIVE by PIC 9(3) COMP, whereas number as a whole is understood as NEGATIVE by PIC S9(3) COMP. That means bit pattern stored in two different data items may appear same, but they may represent altogether two different numbers.Binary simply converted to decimal (calculator) 0, 1, 2,……..32766, 32767, 32768, 32769,…………………..,65534, 65535.PIC 9(3) COMP understands it as decimal 0, 1, 2,……..32766, 32767, 32768, 32769,…………………..,65534, 65535.PIC S9(3) COMP understands it as decimal 0, 1, 2,……..32766, 32767, -32768, -32767,……………-3, -2, -1 . Practice Homework: Try and develop the bit patterns if 157 and -157 are stored in each of the above numeric data types. Try and develop the bit patterns if 892 and -892 are stored in each of the above numeric data types.Section 2: Data storage in PIC S9(01) COMP thru PIC S9(09) COMP – Sample Programs We will try and answer the following questions as sampleDoes the same rule hold good when we move values to USAGE COMP as well. In other words, do PIC S9(05) and PIC S9(04) COMP behave similarly as far as what values they receive from another variable? If PIC S9(05) receives some value, is it mandatory that PIC S9(04) COMP should also be able to receive it? If PIC S9(05) truncates some value, is it mandatory that PIC S9(04) COMP also truncates it as much?PIC S9(N) is a N-digit variable. Is it true for PIC S9(N) COMP as well?Other questionsLargest and smallest numbers (basically range) that can be stored in PIC S9(01) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(02) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(03) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(04) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(05) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(06) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(07) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(08) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(09) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(10) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(11) COMP.First let us straightaway refer to the executed program below and its output for these kinds of variables PIC S9(04) COMP and PIC S9(05) & PIC S9(09) COMP and PIC S9(10)First POSITIVE NUMBERS are considered. Many numbers are taken to test the limit of positive numbers that cobol compiler accepts in these variables.Now let us also observe the output – this time for NEGATIVE NUMBERS. PIC S9(04) COMP and PIC S9(05) & PIC S9(09) COMP and PIC S9(10)Again, many numbers are taken to test the limit of negative numbers that cobol compiler accepts in these variables.Section 3: Observation of Data storage in PIC S9(01) COMP thru PIC S9(09) COMPObservation from the programs: Table 1POSITIVE NUMBERS?SourceDestination?PIC S9(11)PIC S9(04) COMPPIC S9(05)Equal or Not?PIC S9(09) COMPPIC S9(10)Equal or Not?3-digit274274274YES274274YES3-digit999999999YES999999YES4-digit386738673867YES38673867YES4-digit999999999999YES99999999YES5-digit220002200022000YES2200022000YES5-digit327653276532765YES3276532765YES5-digit327663276632766YES3276632766YES5-digit327673276732767YES3276732767YES5-digit32768-3276832768NO3276832768YES5-digit32769-3276732769NO3276932769YES5-digit32770-3276632770NO3277032770YES5-digit38000-2753638000NO3800038000YES5-digit50000-1553650000NO5000050000YES5-digit65533-365533NO6553365533YES5-digit65534-265534NO6553465534YES5-digit65535-165535NO6553565535YES5-digit65536065536NO6553665536YES5-digit65537165537NO6553765537YES5-digit65538265538NO6553865538YES5-digit99999-3107399999NO9999999999YES6-digit123456-761623456NO123456123456YES6-digit9999991695999999NO999999999999YES7-digit3245614-3118645614NO32456143245614YES7-digit9999999-2700999999NO99999999999999YES8-digit123456782491045678NO1234567812345678YES8-digit99999999-793799999NO9999999999999999YES9-digit123456789-1303556789NO123456789123456789YES9-digit999999999-1382599999NO999999999999999999YES10-digit123456789072267890NO12345678901234567890YES10-digit2147483645-383645NO21474836452147483645YES10-digit2147483646-283646NO21474836462147483646YES10-digit2147483647-183647NO21474836472147483647YES10-digit2147483648083648NO-21474836482147483648NO10-digit2147483649183649NO-21474836472147483649NO10-digit2148001234-67021234NO-21469660622148001234NO10-digit9999999999-716999999NO14100654079999999999NO11-digit24680246802-2097446802NO-10895569744680246802NO11-digit99999999999-614599999NO12157521919999999999NOTable 2NEGATIVE NUMBERS?SourceDestination?PIC S9(11)PIC S9(04) COMPPIC S9(05)Equal or Not?PIC S9(09) COMPPIC S9(10)Equal or Not?3-digit-274-274-274YES-274-274YES3-digit-999-999-999YES-999-999YES4-digit-3867-3867-3867YES-3867-3867YES4-digit-9999-9999-9999YES-9999-9999YES5-digit-22000-22000-22000YES-22000-22000YES5-digit-32765-32765-32765YES-32765-32765YES5-digit-32766-32766-32766YES-32766-32766YES5-digit-32767-32767-32767YES-32767-32767YES5-digit-32768-32768-32768YES-32768-32768YES5-digit-3276932767-32769NO-32769-32769YES5-digit-3277032766-32770NO-32770-32770YES5-digit-3800027536-38000NO-38000-38000YES5-digit-5000015536-50000NO-50000-50000YES5-digit-655333-65533NO-65533-65533YES5-digit-655342-65534NO-65534-65534YES5-digit-655351-65535NO-65535-65535YES5-digit-655360-65536NO-65536-65536YES5-digit-65537-1-65537NO-65537-65537YES5-digit-65538-2-65538NO-65538-65538YES5-digit-9999931073-99999NO-99999-99999YES6-digit-1234567616-23456NO-123456-123456YES6-digit-999999-16959-99999NO-999999-999999YES7-digit-324561431186-45614NO-3245614-3245614YES7-digit-999999927009-99999NO-9999999-9999999YES8-digit-12345678-24910-45678NO-12345678-12345678YES8-digit-999999997937-99999NO-99999999-99999999YES9-digit-12345678913035-56789NO-123456789-123456789YES9-digit-99999999913825-99999NO-999999999-999999999YES10-digit-1234567890-722-67890NO-1234567890-1234567890YES10-digit-21474836453-83645NO-2147483645-2147483645YES10-digit-21474836462-83646NO-2147483646-2147483646YES10-digit-21474836471-83647NO-2147483647-2147483647YES10-digit-21474836480-83648NO-2147483648-2147483648YES10-digit-2147483649-1-83649NO2147483647-2147483649NO10-digit-21480012346702-1234NO2146966062-2148001234NO10-digit-99999999997169-99999NO-1410065407-9999999999NO11-digit-2468024680220974-46802NO1089556974-4680246802NO11-digit-999999999996145-99999NO-1215752191-9999999999NOARITH(COMPAT), TRUNC(BIN) used for documenting below tableCOMP fieldsSIZE (# of bits)R A N G EMax no. of digits storedDISPLAY SIZEComments?TotalSignDataTheoretical rangeActual range????????PIC S9(01) COMP PIC S9(02) COMPPIC S9(03) COMPPIC S9(04) COMP16115Minimum: -32768 Maximum: +32767((2 raised to 15) - 1)same55 digitsPIC S9(01) COMP can store all numbers that PIC S9(04) COMP can store. Even PIC S9(02) COMP and PIC S9(03) COMP follow same.?????????PIC S9(05) COMPPIC S9(06) COMPPIC S9(07) COMPPIC S9(08) COMPPIC S9(09) COMP32131Minimum: -2,147,483,648Maximum: +2,147,483,647((2 raised to 31) - 1)same1010 digitsPIC S9(05) COMP can store all numbers that PIC S9(09) COMP can store. Even PIC S9(06) COMP, PIC S9(07) COMP, and PIC S9(08) COMP follow same.?????????PIC S9(10) COMPPIC S9(11) COMPPIC S9(12) COMPPIC S9(13) COMPPIC S9(14) COMPPIC S9(15) COMPPIC S9(16) COMPPIC S9(17) COMPPIC S9(18) COMP64163Minimum: -9,223,372,036,854,775,808Maximum: +9,223,372,036,854,775,807((2 raised to 63) - 1)Minimum: -999,999,999,999,999,999Maximum: +999,999,999,999,999,9991819-digitsPIC S9(10) COMP can store all numbers that PIC S9(18) COMP can store. Even PIC S9(11) COMP, PIC S9(12) COMP, PIC S9(13) COMP, PIC S914) COMP, PIC S915) COMP, PIC S9(16) COMP, and PIC S9(17) COMP follow same.If ARITH(EXTEND), TRUNC(BIN) were used for above, then, even PIC S9(10) COMP thru PIC S9(18) COMP would accept the theoretical range (see discussion in section 5).1. What range of numbers can PIC S9(04) COMP store? PIC S9(04) COMP has a range (-32768 to 32767). That means it can store some 5-digit numbers (though, not all). Since, it can store 5-digit numbers (even if a few), its display shows 5 digits."NO" (in Table 1 and in Table 2) represent those cases where a number stored in PIC S9(05) is NOT same as that stored in PIC S9(04) COMP (even though source of movement to both was same number). Difference is because PIC S9(04) COMP, whenever it sees incoming data to be outside of its range, converts it to a number within the range. When incoming data is within the range, there is no difference between stored value in PIC S9(05) and PIC S9(04) COMP.2. What range of numbers can PIC S9(09) COMP store? PIC S9(09) COMP has a range (-2147483648 to +2147483647) . That means it can store some 10-digit numbers (though, not all). Since, it can store 10-digit numbers (even if a few), its display shows 10 digits."NO" (in Table 1 and in Table 2) represent those cases where a number stored in PIC S9(10) is NOT same as that stored in PIC S9(09) COMP (even though source of movement to both was same number). Difference is because PIC S9(09) COMP, whenever it sees incoming data to be outside of its range, converts it to a number within the range. When incoming data is within the range, there is no difference between stored value in PIC S9(10) and PIC S9(09) COMP.RangesPIC S9(04) COMPPIC S9(05)PIC S9(09) COMPPIC S9(10)?(-32,768 to 32,767) – a few 5-digit numbers also included(-99,999 to 99,999) – all 5-digit numbers included(-2,147,483,648 to +2,147,483,647) – a few 10-digit numbers also included(-9,999,999,999 to +9,999,999,999) – all 10 digit numbers includedBelow is the crux of data movement to PIC S9(04) COMP and PIC S9(09) COMP?PIC S9(04) COMP and PIC S9(09) COMPPIC S9(05) and PIC S9(10)If number is within rangedirectly store it as-is directly store it as-is If number is out of range convert to a number within range ---> store the number to which source is converted totruncate towards left --> store the number to which source is truncated toPIC S9(04) COMP can store 5 digits. It does NOT matter if incoming number has more digits than what PIC S9(04) COMP can store. As an example, even for an 8-digit incoming number, the incoming number is converted to a number within its range, and then gets stored as converted number.PIC S9(09) COMP can store 10 digits. It does NOT matter if incoming number has more digits than what PIC S9(09) COMP can store. As an example, even for a 12-digit incoming number, the incoming number is converted to a number within its range, and then gets stored as converted number. For COMP, If number is out of range, concept of truncation does NOT hold good (in fact it is irrelevant) as number is CONVERTED. Truncation is relevant when you try to store the number but cannot fit it due to length issues. When conversion is carried out, the original number gets lost, so truncation of original number becomes meaningless when conversion is carried out. Conversion (for COMP) and truncation(for USAGE DISPLAY) are two different things.Conversion formulae (when incoming number is outside of range)‘MOD’ means remainder obtained during division (in excel below can be easily calculated).PIC S9(04) COMP (positive number N, outside of (1 to 32767)) MOD((N - 32767),65536) -32769 (negative number N, outside of (-32768 to -1)) MOD((N + 32768),65536) -32768(Note: The above is applicable for PIC S9(01) COMP thru PIC S9(04) COMP)PIC S9(09) COMP (positive number N, outside of (1 to +2147483647)) MOD((N -2147483647),4294967296) -2147483649 (negative number N, outside of (2147483648 to -1)) MOD((N + 2147483648),4294967296) -2147483648(Note: The above is applicable for PIC S9(05) COMP thru PIC S9(09) COMP)Further comments: For PIC S9(04) COMPRange of values stored in PIC S9(04) COMP is from -32768 to 32767 only ( a total of 65536 numbers). This range repeats on either side (positive numbers and negative numbers - see below for explanation). Any number that is outside of this range - numbers less than -32768, and numbers greater than 32767 - , if moved, gets converted (not truncated) to a number within this range as per ruleActual number-98304…..-65536……-32769-32768…..0……3276732768……..65536……98303Number converted to-32768……….0…………32767-32768…..0……32767-32768……….0…………32767?Negative side?Positive sideFor PIC S9(09) COMPRange of values stored in PIC S9(09) COMP is from -2147483648 to +2147483647 only ( a total of 4294967296 numbers). This range repeats on either side (positive numbers and negative numbers - see below for explanation). Any number that is outside of this range - numbers less than -2147483648, and numbers greater than 2147483648 - , if moved, gets converted (not truncated) to a number within this range as per ruleActual number-6442450944……..-4294967296….-2147483649-2147483648…..0……21474836472147483648………4294967296……6442450943Number converted to-2147483648………………0……………2147483647-2147483648…..0……2147483647-2147483648………………0……………2147483647Negative side?Positive sideNow let us answer these questionsDoes the same rule hold good when we move values to USAGE COMP as well. In other words, do PIC S9(05) and PIC S9(04) COMP behave similarly as far as what they receive from another variable? Ans: Rule is same for COMP as well. But before applying three points of the rule, conversion takes place, if required. If value is out of range, conversion happens. If value is within range, no conversion happens. After decision on conversion-or-not is made and applied, rule of numeric movement is applied.If PIC S9(05) receives some value, is it mandatory that PIC S9(04) COMP should also be able to receive it? Ans: It is not necessary. They have different ranges. PIC S905) can store from -99,999 thru +99,999. PIC S9(04) COMP can store -32,768 thru +32,767.PIC S9(05) -99,999…………………………………………………………+ 99,999PIC S9(04) COMP -32,768……………..+32,767Within, -32,768………+32,767, both will store identically.Outside of -32,768……..+32,767 and within -99,999………+ 99,999, PIC S9(04)COMP will convert. PIC S9(05)will store without issues.Outside of -99,999………+ 99,999, PIC S9(04)COMP will convert and store. PIC S9(05) will truncate.Similarly,PIC S9(10) -9,999,999,999…………………………………………………………………………………….+ 9,999,999,999PIC S9(09) COMP -2,147,483,648………………….. +2,147,483,647Within, -2,147,483,648………+2,147,483,647, both will store identically.Outside of -2,147,483,648……..+2,147,483,647 and within -9,999,999,999………+ 9,999,999,999, PIC S9(09)COMP will convert. PIC S9(10)will store without issues.Outside of -9,999,999,999………+ 9,999,999,999, PIC S9(09)COMP will convert and store. PIC S9(10) will truncate..If PIC S9(05) truncates some value, is it mandatory that PIC S9(04) COMP also truncates it as much?Ans: Not really. As an example, if a 6-digit number is moved, then PIC S9(05) will truncate it. But as far as PIC S9(04) COMP is concerned, there is no question of truncation. There is a question of conversion. Truncation (in PIC S9(05) and conversion (in PIC S9(04) COMP) will lead to totally 2 different answers. Reason for the different values in them will not be truncation alone. On one side it is truncated, on the other side, it is converted.PIC S9(N) is an N-digit variable. Is it true for PIC S9(N) COMP as well?Ans: Not really. PIC S9(N) COMP can store (N+1), (N+2)…. Number of digits depending on what N is. PIC S9(01) COMP can store 5 digits.Other questionsLargest and smallest numbers (basically range) that can be stored in PIC S9(01) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(02) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(03) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(04) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(05) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(06) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(07) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(08) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(09) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(10) COMP.Largest and smallest numbers (basically range) that can be stored in PIC S9(11) COMP. Ans: Already explained earlierSection 4: Conclusion on PIC S9(01) COMP thru PIC S9(09) COMPConclusion:When the receiving variable is PIC S9(04) COMP. When the input numbers are in the range (-32768..0…..32767), values moved to it behave as if we are moving to PIC S9(05). No change of value happens.When input numbers are outside of this range, they get converted to bring them back to this range - (-32768…..0…..32767).PIC S9(04) COMP CANNOT store anything outside of this range (-32768..0…..32767)PIC S9(04) COMP CAN store 5-digit positive numbers from 10000 to 32767, not after that.PIC S9(04) COMP CAN store 5-digit negative numbers from -32768 to -10000, not after that.PIC S9(04) COMP CAN store 5-digit numbers (even if not all). Whereas, PIC S9(04) Can only store max of 4-digit numbers, not 5-digit numbers. For COMP variables, we should not relate 9(N) with number of digits it can store. Incoming Positive numbers: 5-digit positive numbers > 32767 (example: 45678, 50000)all 6-digit (example: 456789, 523456)all 7-digit (example: 4567890, 1234567) and so on….all undergo conversion when moved to PIC S9(04) COMP.Like PIC S9(05) applies truncation on all incoming numbers. PIC S9(04) COMP applies conversion on all incoming numbers. Discussion of truncation does not arise as any number, if found outside of range, is converted to a number inside the range. This new number is easily storable.Incoming Negative numbers: 5-digit negative numbers < -32768 (example: -45678, -50000)all 6-digit (example: -456789, -523456)all 7-digit (example: -4567890, -1234567)and so on….all undergo conversion when moved to PIC S9(04) COMP.Like PIC S9(05) applies truncation on all incoming numbers. PIC S9(04) COMP applies conversion on all incoming numbers. Discussion of truncation does not arise as any number, if found outside of range, is converted to a number inside the range. This new number is easily storable.Incoming numbers within the range (-32768..0…..32767) are not converted, and are stored as it is. When the receiving variable is PIC S9(09) COMP. When the input numbers are in the range (-2147483648 to +2147483647), values moved to it behave as if we are moving to PIC S9(10). No change of value happens.When input numbers are outside of this range, they get converted to bring them back to this range - (-2147483648 to +2147483647).PIC S9(09) COMP CANNOT store anything outside of this range (-2147483648 to +2147483647).PIC S9(09) COMP CAN store 10-digit positive numbers from 1000000000 to +2147483647, not after that.PIC S9(09) COMP CAN store 10-digit negative numbers from -2147483648 to -1000000000, not after that.PIC S9(09) COMP CAN store 10-digit numbers (even if not all). Whereas, PIC S9(09) Can only store max of 9-digit numbers, not 10-digit numbers. For COMP variables, we should not relate 9(N) with number of digits it can storePositive numbers: 10-digit positive numbers > +2147483647, all 11-digit, all 12-digit, and so on….all undergo conversion when moved to PIC S9(09) COMP.Like PIC S9(10) applies truncation on all incoming numbers. PIC S9(09) COMP applies conversion on all incoming numbers. Discussion of truncation does not arise as any number, if found outside of range, is converted to a number inside the range. This new number is easily storable.Negative numbers: 10-digit negative numbers < -2147483648all 11-digit, all 12-digit, and so on….all undergo conversion when moved to PIC S9(09) COMP.Like PIC S9(10) applies truncation on all incoming numbers. PIC S9(09) COMP applies conversion on all incoming numbers. Discussion of truncation does not arise as any number, if found outside of range, is converted to a number inside the range. This new number is easily storable.Incoming numbers within the range (-2147483648 to +2147483647) are not converted, and are stored as it is. To assign a valueWe cannot use VALUE clause to assign COMP variable with a value that is outside of its range. Same is true for USAGE DISPLAY variables. The number specified must be within range.Myth broken: PIC S9(N) COMP can only store up to N digits. This is not true. Even PIC S9(01) COMP can store 5 digits. Even PIC S9(05) COMP can store 10 digits.PIC S9(04) COMP can only store up to 4-digit numbers. It can store some of 5-digit numbers as well +10000 to +32767, and from -32768 to -10000.PIC S9(09) COMP can only store up to 9-digit numbers. It can store some of 10-digit numbers as well +100000000 to +2147483647, and from -2147483648 to -100000000.New knowledge:PIC S9(01) COMP thru PIC S9(04) COMP can all store same set of numbers – (-32,768 thru +32,767). It is because anyway they occupy identical-sized memory (16 bits). So, why not allow same range to be stored.PIC S9(05) COMP thru PIC S9(09) COMP can all store same set of numbers – (-2147483648 thru +2147483647). It is because anyway they occupy identical-sized memory (32 bits). So, why not allow same range to be stored.PIC S9(N) – (N = 1, 2, 3) – can do all that PIC S9(04) can do.PIC S9(N) – (N = 5, 6, 7, 8) – can do all that PIC S9(09) can do.As PIC S9(01) COMP, PIC S9(02) COMP, PIC S9(03) COMP, PIC S9(04) COMP – all mean same thing, andPIC S9(05) COMP, PIC S9(06) COMP, PIC S9(07) COMP, PIC S9(08) COMP, PIC S9(09) COMP – all mean same thingDCLGEN recognizes --SMALLNT = PIC S9(04) COMP --INTEGER = PIC S9(09) COMPExisting correct knowledge:PIC 9(N) or PIC S9(N) can store max of N digits.PIC 9(N) COMP-3 or PIC S9(N) COMP-3 can store max of N digits.So, next time when we observe a value, ‘39364’, say, when moved to PIC S9(04) COMP but does not get stored as ‘39364’, we should not be surprised!!!Similarly, next time when we observe a value, ‘2148001234’, say, when moved to PIC S9(09) COMP but does not get stored as ‘2148001234’, we should not be surprised!!!Section 5: Effect of ARITH(EXTEND)Now let’s study what effect ARITH(EXTEND) has.So, far we have seen declarations up to 18 bytes and data processed up to 18 digits. Can we increase the capability of data processed? In other words, can data of more number of digits be stored and processed?ARITH(EXTEND) allows for the possibility of EXTENDING the memory allotment for numeric data items, beyond maximum size allowed by ARITH(COMPAT). This results in extending the range of numbers that can be stored in a numeric data item.1. To make COBOL program accept more than 18 digits in a numeric data item, compiler option ARITH(EXTEND)should be in effect. We can supply it from PARM option to IGYCRCTL. 2. Default option is ARITH(COMPAT). ARITH(COMPAT): Range is to declare data items up to 18 digits. 18 digits includes before and after decimal digits. Total number of digits (before and after decimal) should not exceed 18.ARITH(EXTEND): Range is extended to declare data items up to 31 digits. 31 digits includes before and after decimal digits. Total number of digits (before and after decimal) should not exceed 31.A few programs are tried out for this purpose. See attached text doc.As regards numeric datatypes we normally come across, these can be divided into 3 animals (there are more animals though, in the COBOL jungle!). These normally used animals are:First animal - USAGE DISPLAYSecond animal - USAGE COMPThird animal - USAGE COMP-3USAGEWhere ARITH(COMPAT) and ARITH(EXTEND) are identical in behavior?Where ARITH(COMPAT) and ARITH(EXTEND) are NOT identical in behavior?DISPLAYFor 1. PIC 9(N) – N <=182. PIC S9(N) – N <=183. PIC S9(M)9(N) – (M+N) <=18ARITH(COMPAT) and ARITH(EXTEND) behave identically – for their computation and DISPLAYARITH(EXTEND) allows following (which ARITH(COMPAT) does NOT allow)1. PIC 9(19) thru PIC 9(31) to be declared2. PIC S9(19) thru PIC S9(31) to be declared3. PIC S9(M)V9(N) to be declared – (19 <= M+N <= 31)4. Number of significant digits to extend beyond 18 but fewer than 32 significant digits – before and after decimal counted.???COMPPIC S9(01) COMP thru PIC S9(09) COMPARITH(COMPAT) or ARITH(EXTEND) - respective ranges of PIC S9(01) COMP thru PIC S9(09) COMP stay same.1. PIC S9(01) thru PIC S9(04) COMP - Range is (-32,768 thru +32,767)2. PIC S9(05) thru PIC S9(09) COMP - Range is -2147483648 thru + 2147483647)DISPLAY and computation are also same.PIC S9(10) COMP thru PIC S9(18) COMPTheoretical range in 64 bits occupied by each of PIC S9(10) COMP thru PIC S9(18) COMP-9,223,372,036,854,775,808 Maximum: +9,223,372,036,854,775,807((2 raised to 63) - 1)When compiling using ARITH(COMPAT) option Actual Range of PIC S9(10) COMP thru PIC S9(18) COMP was limited to -999,999,999,999,999,999 thru +999,999,999,999,999,999. This was because when ARITH(COMPAT) is used, COBOL does NOT even accept more than 18 digit numbers at all. Theoretical minimum and maximum values (in 63 bits of PIC S9(10) COMP thru PIC S9(18) COMP fields) are both 19 digits. But as COBOL does NOT permit (when ARITH(COMPAT) is used) more than 18 digits, no 19-digit number of the range is permitted.--from +1,000,000,000,000,000,000 and up to +9,223,372,036,854,775,807 are NOT allowed--from -1,000,000,000,000,000,000 and up to -9,223,372,036,854,775,808 are NOT allowedWhen compiling using ARITH(EXTEND) option, 1. Actual Range of PIC S9(10) COMP thru PIC S9(18) COMP is extended from: Minimum: -999,999,999,999,999,999 Maximum: +999,999,999,999,999,999to : Minimum: -9,223,372,036,854,775,808 Maximum: +9,223,372,036,854,775,807((2 raised to 63) - 1)2. Also, each of these can accommodate the new range - PIC S9(10) COMP thru PIC S9(18) COMPFor COMP, declaration of more than PIC S9(18) COMP is not allowed, even with ARITH(EXTEND) option.???COMP-3?For 1. PIC 9(N) COMP-3 – N <=182. PIC S9(N) COMP-3 – N <=183. PIC S9(M)9(N) COMP-3 – (M+N) <=18ARITH(COMPAT) and ARITH(EXTEND) behave identically – for their computation and DISPLAY?ARITH(EXTEND) allows following (which ARITH(COMPAT) does NOT allow)1. PIC 9(19) COMP-3 thru PIC 9(31) COMP-3 to be declared2. PIC S9(19) COMP-3 thru PIC S9(31) COMP-3 to be declared3. PIC S9(M)V9(N) COMP-3 to be declared – (19 <= M+N <= 31)4. Number of significant digits to extend beyond 18 but fewer than 32 significant digits – before and after decimal counted.?ARITH(COMPAT)ARITH(EXTEND)DISPLAYUp to 18 digit-declarations and up to 18-digit processing allowed.More than 18-digit declarations and more than 18-digit processing PUp to 18 digit-declarations and up to 18-digit processing allowed.Up to 18 digit-declarations only. BUT PRMISSION GIVEN TO PROCESS A FEW 19-DIGIT NUMBERS PERMITTED UP TO THEORETICAL LIMITCOMP-3Up to 18 digit-declarations and up to 18-digit processing allowed.More than 18-digit declarations and more than 18-digit processing allowed.In summary, ARITH(EXTEND) helps Makes possibility of extending capability of storing more than 18 digits. But this gift is only given to 2 of above three animals – viz. USAGE DISPLAY and USAGE COMP-3. USAGE COMP animal is benefitted in a way that the below members of its family - PIC S9(10) COMP thru PIC S9(18) COMP – find themselves holding additional numbers. Following (extra numbers) 19-digit numbers are allowed for these animals.+1,000,000,000,000,000,000 and up to +9,223,372,036,854,775,807-1,000,000,000,000,000,000 and up to -9,223,372,036,854,775,808What ARITH(EXTEND) cannot do for us:It cannot allow USAGE COMP animal to be declared with more than 18 digits in PIC clause. Which means following declaration is invalid A PIC S9(19) COMP VALUE 1234567890123456789.It cannot allow USAGE COMP animal to process outside of theoretical maximum range. It cannot allow COMP to store 20 digits or more. Section 6: Effect of TRUNC(BIN) or TRUNC(STD)Now let’s study what effect TRUNC(BIN) or TRUNC(STD) have.TRUNC option talks about truncation, or cutting short, the range of numbers that can be stored in a numeric data item.Firstly, TRUNC option only has effect on COMP fields (remember I am only talking about 3 animals – DISPLAY, COMP, and COMP-3!!!). Out of these, DISPLAY or COMP-3 are not affected by TRUNC option.There are 2 separate things about a memory:Size of Memory allotted to a variable to store data.Range of data that this memory can accommodate.When compilation is done using TRUNC(STD), memory allotment rule to COMP variables follows same rule as when TRUNC(BIN) option is used. For example, PIC S9(1) COMP, it will continue to occupy 2 bytes only. That means size of memory allotment is not changed. What changes from TRUNC(BIN) to TRUNC(STD) is the range of values that PIC S9(01) COMP can accept.PIC S9(01) COMP --------------------------TRUNC(BIN) - Range is (-32,768 thru +32,767)TRUNC(STD) - Range is (-9 thru +9)So, as we see range of numbers stored is what is affected by TRUNC option. Size of memory is NOT affected. Size of memory utilized remains same.It is like this. A 10 m long room can accommodate up to 10m long box. But as per a rule passed, only up to max 5m boxes long are permitted into the box. More than 5m boxes are cut(to 5m size box) before they are allowed to enter. So, room size is NOT changed. Length of containers permitted is restricted.DISPLAY/COMP-3: In the case of DISPLAY/COMP-3, things are simple. Count how many 9’s are there in the PICTURE definition. If number of digits in incoming number exceeds number of 9’s in the PICTURE definition, then apply truncation rule to drop excess digits on left. So, the reference to decide truncation is number of 9’s in PICTURE definition. This is standard rule of storing. COMP: But we have already seen that in the case of COMP, number of 9’s in PICTURE definition is NOT taken as criterion to decide what can be dropped. Here truncation is governed by a separate rule – binary rule of storing. This rule says that if incoming number exceeds maximum number permitted inside the memory allotted, then truncation happens. And we have seen number of digits in maximum number is GREATER THAN number of 9’s In PICTURE definition.TRUNC(STD) means truncate using standard rule – which is, as per number of 9’s present in PICTURE definition.TRUNC(BIN) means truncate using binary rule – that is, if incoming number exceeds maximum number allowed as per binary rules of storage.Default chosen for TRUNC may vary from system to system. Observe it carefully. In one system, I did not pass TRUNC from PARM, it took default as TRUNC(BIN). In another system, it took the default as TRUNC(STD). So, observe it carefully.We have seen that range of numbers in a COMP field can be different from that of DISPLAY/COMP-3 for the same PIC definition. In fact, any COMP declaration CAN store more range of numbers than what its DISPLAY/COMP-3 declaration counterparts can store.As an example, PIC S9(8) can only store -99,999,999 thru +99,999,999. Which means 8-digit numbers. Larger numbers undergo truncation. Truncation is governed by number of 9’s (in this case 8).PIC S9(8) COMP can store from some 10-digit numbers also. If we want PIC S9(08) COMP to also follow how PIC S9(08) behaves, then TRUNC(STD) is to be used. If TRUNC(STD) is used, then PIC S9(08) COMP will not accept any 9 or higher digit numbers. Its range of numbers will be -99,999,999 thru +99,999,999, which is for PI S9(08).TRUNC option cannot alter the range of DISPLAYPIC 9(N)PIC S9(N)PIC 9(M)V9(N)PIC S9(M)V9(N)COMP-3PIC 9(N) COMP-3PIC S9(N) COMP-3PIC 9(M)V9(N) COMP-3PIC S9(M)V9(N) COMP-3It can alter the range ofPIC 9(N) COMPPIC S9(N) COMPPIC 9(M) COMPPIC S9(M) COMP----- That means TRUNC does NOT affect DISPLAY/COMP-3 fields, in any way.In summary, if TRUNC(STD) is used, then even for a COMP field, developer feels as if it is a DISPLAY/COMP-3 field. Truncations are governed by number of 9’s in the PICTURE definition for COMP fields, and they behave (outwardly) as DISPLAY/COMP-3 fields. Remember internal storage is still in binary format in them. Only the range of numbers stored is cut short. (there are 2 worksheets in above excel file) Section 7: HEX ON analysisWe often analyze data in a file in HEX ON mode. This is especially for fields that are non-DISPLAY types, like COMP, COMP-3 etc..Here again we should be able to read the data in decimal form. Because that is what we understand. But data shown is in hexadecimal form. So, we should clearly know how to convert this hexadecimal number to decimal number. Analysis of USAGE DISPLAY and COMP-3 fieldsThis is relatively easy as for each digit there is a corresponding Hexa decimal value shown. One can easily convert hexadecimal number to decimal number.Analysis of COMP fieldsMove a value to a COMP field.Identify (as per ARITH and TRUNC options) if this value will be accepted as it is, or it will undergo truncation before acceptance.Whatever decimal value is accepted is what gets shown in DISPLAY statement (DISPLAY done on the variable).The file (in HEX ON mode) shows hexadecimal equivalent of the stored decimal number.PIC 9(1) COMP thru PIC 9(18) COMPFeed the hexadecimal value obtained from file into calculator. Compute the equivalent decimal value in the calculator. You will find that the decimal value as shown by the calculator will be what DISPLAY statement (actually stored) will also show. Remember only 0 and positive decimal numbers get stored here. There is a unique hexadecimal number for every decimal number here. Remember also that what you move into the variable may or may not get stored. If truncation is there, then what you move will be different from what gets stored.Decimal - what you move(A) --- Decimal that gets stored(B, shown in DISPLAY) ---- Hexa decimal form (HEX ON). | Calculator’s decimal value (C)A and B may or may not match. B and C will always match.PIC S9(1) COMP thru PIC S9(18) COMPHere calculator’s decimal value and your decimal value may not match. This is true even if your value was accepted by the COMP variable. This case is true for negative numbers. For positive numbers, your decimal value and calculator’s decimal value will match. Values will be same as obtained for unsigned COMP fields.Decimal - what you move(A) --- Decimal that gets stored(B, shown in DISPLAY) ---- Hexa decimal form (HEX ON). | Calculator’s decimal value (C)A and B may or may not match. B and C will always match for positive numbers. B and C will NOT match for negative numbers.A.If we do not know whether a COMP field is signed or not, then remember that by just seeing hexadecimal value in the file for this field, we cannot conclude whether it is corresponding to a signed or if it is corresponding to an unsigned COMP field. For example, if we find X’6F82’ in the file. X’6F82’ can come bystoring +28546 in an signed COMP fieldstoring +28546 in an unsigned COMP fieldHere we ARE able to predict the exact decimal value. But still cannot predict the sign-ness or unsign-ness of field.Similarly, if we find X’8000’ in the file. X’8000’ can come by storing +32768 in an signed COMP fieldstoring -32768 in an unsigned COMP fieldHere we are NOT able to predict the exact decimal value also.So, hex values can be misleading sometimes.B.By seeing Hexadecimal values, we cannot predict number of 9’s in COMP field.Example, PIC S9(02) and PIC 9(02), PIC S9(03) – all show 2 bytes in file.C.You know that a field is numeric. But you do not know whether it is COMP, COMP-3, or DISPLAY. You also do not know whether it is signed or unsigned. You also do not know the number of 9’s in the PICTURE? Can we predict the PICTURE definition by looking at the hexadecimal value?Ans: Answer is No.Refer to the table shown below.?Nature of fieldBasic PICTURE definitionsAllowed 'decimal' characters (without HEX ON mode)allowed Hexadecimal characters (in HEX ON mode)ExampleDISPLAYUnsignedPIC 9(N)PIC 9(N)V9(M)0 thru 9F(in odd numbered nibbles from left)0 thru 9(in even numbered nibbles from left)Ex: +123X'F1F2F3'?SignedPIC S9(N)PIC S9(N)V9(M)0 thru 9, A thru RF(in odd numbered nibbles from left, except second from right)0 thru 9(in even numbered nibbles from left, except rightmost)C/D (second nibble from right)0 thru 9(rightmost nibble)Ex: -123X'F1F2D3'COMP-3UnsignedPIC 9(N) COMP-3PIC 9(N)V9(M) COMP-3hard to figure out….junk shown0 thru 9F(rightmost nibble)Ex: 123X'00123F'?SignedPIC S9(N) COMP-3PIC S9(N)V9(M) COMP-3hard to figure out….junk shown0 thru 9. C/D(rightmost nibble)Ex: -123X'00123D'COMPUnsignedPIC 9(N) COMPhard to figure out….junk shown0 thru 9, A thru FEx: 123X'007B'?SignedPIC S9(N) COMPhard to figure out….junk shown0 thru 9, A thru FEx: -123X'FF85'Let’s take an example to prove this point. Hexadecimal value shown is X’F0FF’.It is a 2-byte field. Comparing to the table above, we find that this cannot be coming from DISPLAY Unsigned. This cannot be coming from DISPLAY signed. This cannot be coming from COMP-3 Unsigned. This cannot be coming from COMP-3 Signed. So, the only possibility is that it is coming from a COMP field. Can we say Signed COMP or Unsigned COMP. No, we cannot. Why? Use calculator to convert ‘F0FF’ to decimal. It is ‘61695’. This could be coming from PIC 9(1) COMP thru PIC 9(4) COMP provided program is compiled with TRUNC(BIN). It could also be coming from PIC S9(1) COMP thru PIC S9(4) COMP. In this case the decimal value will not be 61695, but will be -3841. So, here answer is NO.Hexadecimal value shown is X’F0F1’.It is a 2-byte field. Comparing to the table above, it could beDISPLAY Unsigned -> Decimal value = ‘01’COMP Unsigned -> Decimal value = 61681COMP Signed -> Decimal value = -3855So, here also answer is NO.Hexadecimal value shown is X’1234’.It is a 2-byte field. Comparing to the table above, it is more refined. That is, we can definitely say that it is COMP field. But can we say whether signed or unsignedCOMP Unsigned -> Decimal value = 4660COMP Signed -> Decimal value = 4660So, here decimal value is same. But we cannot say if coming from unsigned or signed.So, here also answer is NO.So, the conclusion is that if we at least know that the field is signed or not, then we may be able to say about the USAGE type. But that also very remote chance. Number of 9’s is also not knowable for sure.(There are three sub-sheets in this excel)Section 8: What would happen if COMP variable had a fractional part?This is hardly used. Perhaps never. But let’s analyse if COMP can only store integers or fractions as well. If it can store fractions, how do they behave?COMP variables can be declared with fractional part – and they can store fractional numbers as well.Memory Size: Memory size rules for a COMP variable that has a fractional part is same as that for COMP variable that is without a fractional part. Which means number of bytes allocated only depends on the total number of 9’s in the PICTURE definition. PIC 9(03)V9(01) COMP, PIC 9(02)V9(02) COMP, PIC 9(01)V9(03) COMP, PIC V9(04) COMP all occupy 2 bytes. Their signed versions also occupy 2 bytes only.Range of Data Storage:TRUNC(BIN)We know that range of PIC 9(04) COMP is from 00000 thru 65535.We know that range of PIC S9(04) COMP is from -32768 thru 32767.In order to understand range of PIC 9(N)V9(M) COMP – [N+M = 4], it is enough to remember that number of decimal digits that can be stored after decimal cannot exceed the number of 9’s declared after decimal. We know the range of PIC 9(N)V9(M) COMP for M = 0. When M > 0, the new range is derived from original range only(M=0). In the new range, for M > 0,decimal will move left wards by as many digits as the number of 9’s after decimal.For example, range of PIC 9(04) COMP is 0 thru 65535.So, as per this rule:PIC 9(03)V9(01) COMP - will have range from 0 thru 6553.5.PIC 9(02)V9(02) COMP - will have range from 0 thru 655.35.PIC 9(01)V9(03) COMP - will have range from 0 thru 65.535.PIC V9(04) COMP - will have range from 0 thru 6.5535.Similarly, 5 thru 9-digited and 10 thru 18-digited PICTURE clauses also behave as per their respective ranges.PIC S9(03)V9(01) COMP - will have range from -3276.8 thru 3276.7.PIC S9(02)V9(02) COMP - will have range from -327.68 thru 327.67.PIC S9(01)V9(03) COMP - will have range from -32.768 thru 32.767.PIC SV9(04) COMP - will have range from -3.2768 thru 3.2767.Similarly, 5 thru 9-digited and 10 thru 18-digited PICTURE clauses also behave as per their respective ranges.TRUNC(STD)As with variable declarations without the decimal part, here also, COMP variables behave as if ‘COMP’ is removed from them. As examples:PIC 9(03)V9(01) COMP will behave as PIC 9(03)V9(01) behaves -- Range will be from 0 thru +999.99.PIC S9(03)V9(01) COMP will behave as PIC 9(03)V9(01) behaves -- Range will be from -999.99 thru +999.99. Section 9: Answered QuestionsQ. If I want to process a 20-digit number using a single variable, what should I do?A. Use either USAGE DISPLAY or USAGE COMP-3. Use ARITH(EXTEND) during compilation. COMP cannot help here.Q. I want to utilize PIC S9(18) COMP to be able to store those 19-digit values that are theoretically allowed?A. Use ARITH(EXTEND) and TRUNC(BIN) during compilation. If ARITH(EXTEND) is used but TRUNC(STD) is used, then program will still process 18 digit numbers max. Moving a 19-digit number will truncate one digit (on left).Q. I want to process a 35-digit number using a single variable. What should I do?A. No one can help here. We cannot process more than 32 digit numbers (before and after decimal counted). Perhaps need to think of using multiple variables method etc…Q. I am using ARITH(COMPAT). Can I process an 18-digit number?A. Yes. All three animals – DISPLAY, COMP, COMP-3 – can do this. ARITH(COMPAT) is default option. To pass, ARITH(EXTEND) we must pass from JCL.Q. I am using ARITH(EXTEND). Can I store a 20-digit number in PIC S9(19) COMP-3?A. No. Irrespective of ARITH option used, USAGE DISPLAY and USAGE COMP-3 can only store as many digits as there are 9’s in PICTURE clause.Q. I am using ARITH(COMPAT). Can I declare a PIC 9(19) but process a 18-digit number through it?A. No. None of three animals can help here. When ARITH(COMPAT) is used, any of three animals can at best declarePIC 9(18) PIC S9(18)PIC 9(N)V9(M) – (N+M) <=18 PIC S9(N)V9(M). – (N+M) <=18In order to process above request, below options are possiblePIC 9(19)PIC 9(19) COMP-3And compile using ARITH(EXTEND) in either case.PIC 9(19) COMP is not declarable. This animal never goes beyond PIC 9(18) COMP.Q. I am observing that my program does not allow me to declare PIC clause with greater than 18 digits. I want to process a 20 digit number. What should I do?A. This is happening because compiler option ARITH uses COMPAT. If field under consideration is COMP, then nothing can be done. COMP cannot be declared beyond PIC S9(18) COMP anyway. If field under consideration is DISPLAY or COMP-3, then change compiler option ARITH. Use ARITH(EXTEND) in order to make DISPLAY / COMP-3 fields accept PICTURE clause greater than 18 digits. You must use PIC S9(20) or above and then assign a 20-digit value to it. PIC S9(19) and PIC S9(19) COMP-3 cannot store a 20-digit number.Q. I have copied a program from one machine (A) to another machine (B). In machine A, it was able to process a 9-digit number. But not anymore in machine B. Why?A. Let me divide the discussion into 2 piecesUSAGE DISPLAY / USAGE COMP-3To be able to process a 9-digit number, minimum any of following should be used. PIC 9(9)PIC S9(9)PIC 9(9) COMP-3PIC S9(9) COMP-3Any value under ARITH (COMPAT or EXTEND) , and any value for TRUNC (BIN or STD) cannot cause the problem you have observed. That means the variable under question is a neither a USAGE DISPLAY nor a USAGE COMP-3 type. It is a COMP variable.The problem is that you had a COMP variable that might have been declared in any of following waysPIC S9(05) COMPPIC S9(06) COMPPIC S9(07) COMPPIC S9(08) COMPOn machine A, compiler option was TRUNC(BIN). Any of these variables can process a 9-digit number when TRUNC(BIN) is used. (Remember PIC S9(01) COMP thru PIC S9(04) COMP cannot process a 9-digit variable). Due to this, when you moved a 9-digit number into the variable, it was able to accept it and process it. But on machine B, TRUNC(STD) was used. Due to this, when you moved a 9-digit number into the variable, truncation happened in following way (check out which one!!)PIC S9(05) COMP – 9-digit number was truncated to 5 digits.PIC S9(06) COMP – 9-digit number was truncated to 7 digits.PIC S9(07) COMP – 9-digit number was truncated to 8 digits.PIC S9(08) COMP – 9-digit number was truncated to 9 pile using TRUNC(BIN) – override from PARM of IGYCRCTL - and you will be good to go!!Q. I am using ARITH(EXTEND), can I declare as below.01 DISTANCE-OF-STAR PIC S9(20) VALUE 12345678901234567890123.A. No. PICTURE definition must be compatible with VALUE clause. As it is a USAGE DISPLAY field, number of digits in PICTURE must be greater than or equal to number of digits in VALUE clause. If it were a USAGE COMP-3, same argument hold good.If it were a COMP field, it is invalid declaration because PIC S9(18) COMP is maximum we can declare. Q. Can I ever process 10-digit numbers through a PIC 9(9)?A. No. This variable can at best store 999,999,999 (maximum value allowed = number of 9’s in PICTURE).Q. Can I ever process 10-digit numbers through a PIC 9(9) COMP-3?A. No. This variable can at best store 999,999,999 (maximum value allowed = number of 9’s in PICTURE).Q. Can I ever process 10-digit numbers through a PIC 9(9) COMP?A. Yes. PIC 9(9) COMP combined with TRUNC(BIN) can achieve this. ARITH (COMPAT or EXTEND) does not impact here. Remember not all 10-digit numbers can be processed. Only up to +2147483647 can be processed. If TRUNC(STD) is used, then no 10-digit number can be processed. Max is 9-digit number.Q. Can I ever process 11-digit numbers through a PIC 9(9)?A. No. This variable can at best store 999,999,999 (maximum value allowed = number of 9’s in PICTURE).Q. Can I ever process 11-digit numbers through a PIC 9(9) COMP-3?A. No. This variable can at best store 999,999,999 (maximum value allowed = number of 9’s in PICTURE).Q. Can I ever process 11-digit numbers through a PIC 9(9) COMP?A. No. This variable can at best store 999,999,999 (TRUNC(STD)) or +2147483647(TRUNC(BIN)) none of which is 11-digit number.Q. I have copied a program from one machine (A) to another machine (B). My program received ‘INDIA IS MY COUNTRY’ from JCL. On machine A, I was able to get correct value of length( as 19) into the program in the length variable. On machine B, length variable showed me length of data passed as 9. Why? I have used length variable as PIC S9(01) COMP for the length variable and I very well know that even PIC S9(01) COMP can store any number that PIC S9(04) COMP can store, then why the length is not shown correctly. Please note that my program is able to receive the parameter value correctly. It is only length that is not indicated correctly. So, length of data received(9), and actual data received(INDIA IS MY COUNTRY) are not consistent.A. JCL passes length correctly. It must have passed 19 only. But when this starts getting into the program, system checks the rules for COMP processing. You are right in saying that even PIC S9(01) COMP can store any number that PIC S9(04) COMP can store, and, therefore, it should be able to accept 19 into the length variable. But it is possible only when TRUNC(BIN) is used during compilation. If TRUNC(STD) is used instead, then this variable behaves like a true 1-digit variable that cannot accept anything beyond max 1-digit number, that is 9. So, ‘19’ is sent by JCL. But only one digit is acceptable to COBOL variable. Right justification rule makes ‘9’ to be stored and ‘1’ is truncated.Q. PIC S9(01) COMP - I know that it occupies 2 bytes. Same thing with PIC S9(02) COMP, PIC S9(03) COMP and PIC S9(04) COMP. Does the memory allotment change if I choose different option for ARITH and/or a different option for TRUNC?A. No. Size of Memory allocated for COMP is in no way governed by options chosen for ARITH or option chosen for TRUNC. The maximum thing that option chosen in a TRUNC can do is that it can limit the contents that you put inside these memories. Each of them store easily 4 digit numbers easily when RNC(BIN) is in effect. But the moment TRUNC(STD) is used, each of them start accepting numbers differently. PIC S9(01) COMP will only max accept 1-digit (-9 thru +9), PIC S9(02) COMP will only max accept 2-digits (-99 thru +99), PIC S9(03) COMP will only max accept 3-digit s(-999 thru +999), PIC S9(04) COMP will only max accept 4-digits (-9999 thru +9999).When TRUNC(STD) is used, memory allotment rule does NOT change but rule for acceptance of a number into it changes.Q. I need to declare a numeric field that can accommodate a 5-digit number . What are the options possible for me to declare a PIC that uses minimum 9’s?A. USAGE DISPLAYPIC 9(05) if only positive numbers are going to come.PIC S9(05) if both positive and negative numbers are going to comeUSAGE COMP-3PIC 9(05) COMP-3, if only positive numbers are going to come.PIC S9(05) COMP-3, if both positive and negative numbers are going to comeUSAGE COMPPIC S9(06) COMPQ. I need to declare a numeric field that can accommodate an 8-digit number . What are the options possible for me to declare a PIC that uses minimum 9’s?A. Keep track of TRUNC option for this.USAGE DISPLAYPIC 9(08) if only positive numbers are going to come.PIC S9(08) if both positive and negative numbers are going to comeUSAGE COMP-3PIC 9(08) COMP-3, if only positive numbers are going to come.PIC S9(08) COMP-3, if both positive and negative numbers are going to come TRUNC option does NOT matter for USAGE DISPLAY and USAGE COMP-3.USAGE COMP PIC 9(05) COMP, if only positive numbers are going to come. PIC S9(05) COMP, if both positive and negative numbers are going to come[Make sure TRUNC(BIN) is used. TRUNC(STD) will make it NOT accept anything more than 5-digits].If TRUNC(STD) is used, make sure to use minimum of PIC 9(08) COMP or PIC S9(08) COMP.Q. 01 WS-VAR PIC S9(02) COMP.DISPLAY LENGTH OF WS-VARDISPLAY WS-VARA. ‘LENGTH OF’ is an internal function of cobol that helps to know the size of memory that cobol has allocated to a data item. Answer is In number of bytes allocated. In this case, WS-VAR occupies 2 bytes and, hence, answer of DISPLAY LENGTH OF WS-VAR will be 2.DISPLAY WS-VAR displays the contents presents in WS-VAR. If program is compiled with TRUNC(BIN), DISPLAY WS-VAR will show 5 digits. If program is compiled with TRUNC(STD), DISPLAY WS-VAR will show 1 digit.If the above variable is stored as a field on a file, then it will occupy 2 bytes there.Q. PIC S9(N) COMP.When it is compiled with TRUNC(BIN) it stores internally in binary format. When it is compiled using TRUNC(STD), does internal storage method change?A. No. The method of storage does not change. COMP will always follow binary storage algorithm. BIN and STD only govern which decimal number can be stored and which cannot be stored. Only range is what gets changed from BIN to STD. Once decision is made to store a given number, the binary conversion is done, and binary bit pattern is stored. Q. I have a PIC S9(04) COMP field that is present in a file record. When I open the file I see it as holding 2 bytes. But when I read the file in my program and display the field from there, display shows 5 digits in SYSOUT. The number stored is only a 3-digit number inside the variable. Then why is it that in one place (file) I see 2 bytes) and in the other place (SYSOUT) it shows me 5 digits (5 bytes).A. A variable has 2 properties associated with it. memory sizedata present these are two different things.Simple answer to the question is that file is meant to be responsible for showing size of memory held by variable. So, it shows us clearly that variable is holding 2 bytes of memory. Whereas SYSOUT is meant to be responsible for showing clearly the data that is actually stored in the variable. So, it shows 5 digits.SYSOUT is meant for a different purpose than file, as regards showing properties of a variable. One(file) shows first property clearly (regardless of whether second property is shown clearly or not). The other(SYSOUT) shows second property clearly (regardless of whether first property is shown clearly or not)Elaboration:File is more interested in showing to us size of memory that is holding the data. It shows you memory clearly. By seeing the file, you get clarity about how much size of memory is allocated by system to your variable. So, you get clarity on memory when you see the file. But this enforcement puts restriction on the capability of file to show data clearly. So, it does not take guarantee to show the data in a format that you and I can comfortably read. For some fields (USAGE DISPLAY) you and I may be able to read data comfortably, but for some others(non-USAGE DISPLAY) not.Whereas is DISPLAY is more interested in showing you the data in a comfortable manner. That means DISPLAY puts effort to ensure that we get to see each digit clearly. It does not bother to take responsibility of showing to us how many bytes held this data in the background. In fact all non-USAGE DISPLAY variables are converted, temporarily, to USAGE DISPLAY types to be able to show data comfortably.So, one person (file) takes one responsibility - of showing information on memory clearly. The other person (SYSOUT) takes the other responsibility - of showing the data clearly. Tools like File Aid, File manager take both responsibilities. They show us data stored as well as size of memory against that data.It is like – We see blueprint of a house. That is like seeing memory size. We get to know easily how many rooms are there, what their sizes are. This is like seeing file.Later you see the photo of only luggage. Here we do not know how much luggage was kept in which room. This is like seeing SYSOUT.When we see the actual house with luggage, it is like seeing File Aid. We can see size of room also and also what data is kept in how much space. Memory size is also known, and data is also in readable format.?File viewingDISPLAY (SYSOUT) viewingArea of FocusMemoryDataWhat is clear?It is clear how much size of memory a variable holds. It is clear what data is stored (all types of fields)what is not clear?It may not be clear what data is stored (true for other-than-USAGE DISPLAY fields)It may NOT be clear how much size of memory the variable holds. USAGE DISPLAYClarity on data available for USAGE DISPLAY fieldsnon-USAGE DISPLAYClarity on data NOT available. Need to use HEX ON and other methods to determine the dataClarity on data available?system-oriented (memory conservation) Human-oriented(comfort in viewing) File is a memory area. A file is meant to hold a region of memory (mostly permanent) to store data. File can be empty initially. Data may come later into it. In initial days of programming and storing data, lot of effort was made to use this memory efficiently so that lesser memory could store comparatively more data. Effort was made to find out ways how to store data in a compressed manner. COMP variable was created as an outcome of this effort. Assuming your program is using TRUNC(BIN) while performing compilation. PIC S9(04) COMP is allotted 2 bytes, regardless of TRUNC option chosen. As this variable is part of your file record, that means as and when records are written to the file, file reserves on each record 2 bytes of memory for this variable. Data going into this variable on each record is stored into these 2 bytes only. Next thing to be answered is that what size of data can you store in a given size of memory. A program compiled with TRUNC(BIN) allows provision for storing, in PIC S9(04) COMP, up to certain 5-digit numbers(-32,768 thru -1, 0, +1 thru 32,767). So, as you can see now, that the memory reserved was 2 bytes. But number of digits moved into it can be as high as 5. Notice that when we talk of size of data stored, we do NOT speak in terms of bytes. We speak in terms of digits. It is because we human beings understand digits, and it is the digits that get stored.. A digit has no meaning for a computer. It only understands bits and bytes. For us, we are not interested in seeing bits and bytes 1’s and 0’s). We want to see the digits. For us, 1 digit means size=1, 2-digit means size=2 and so on. But as programmers, we should understand that what is size=1 for us is NOT NECESSARILY size=1 for system. That means it may sometimes be true, but it need not always be. For us, SIZE=1 means 1-digit For system, SIZE=1 means 1 byte.Can we equate 1-digt = 1 byte when data is stored in the file? The answer is yes sometimes, and not on some other times. ‘Yes’ is when USAGE of the variable is DISPLAY. And ‘No’ is when the USAGE of the variable is other than DISPLAY. USAGE of fieldSIZE?for usfor systemDISPLAYIdenticalnon-DISPLAYDifferentDISPLAY means show what you would have shown had the variable been of type USAGE DISPLAY. A USAGE DISPLAY variable NEVER undergoes any conversion when it is taken from a storage location (either in a physical file or inside a variable that is declared inside a program) to a display location (SYSOUT).There is no need for any conversion because inside the file or inside the program the data is in USAGE DISPLAY format, and when it is displayed, then also it is in USAGE DISPLAY format.DISPLAY statement converts, if required, any non- USAGE DISPLAY to a USAGE DISPLAY. This happens temporarily only and things are shown in SYSOUT in USAGE DISPLAY format. Inside the program, data variable may still be in non-DISPLAY format.Q. I use DISPLAY statement to display a file record. There is a PIC S9(04) COMP field in the record that stores 172 in it. But I cannot see ‘172’ anywhere in the record shown on SYSOUT. I see some junk values in the places intended for the COMP variable. But when I use DISPLAY on this COMP variable that is holding ‘172’, it is shown to me as ‘00172’. Why?A. First of all, from your question it is clear that you are using TRUNC(BIN).When you use DISPLAY statement on a file record(01 level), you are using DISPLAY statement on a variable that is of USAGE DISPLAY. Group level variables are considered by system as alphanumeric, and we know that alphanumeric variable default to USAGE DISPLAY. Since, it is already USAGE DISPLAY, system does NOT do any reformatting of data present inside record, and data of entire record is shown exactly as it is present in the file. So, you see the data present in the COMP variable as some junk values.When DISPLAY statement is applied on the COMP variable, system finds that it is not of USAGE DISPLAY. So, system converts the variable temporarily to a USAGE DISPLAY type. It converts to PIC S9(05) COMP. Why does it convert to PIC S9(05) COMP, and not to PIC S9(04) COMP? It is because system knows that program was compiled with option TRUNC(BIN), therefore, range of numbers allowed in it is from -32,768 to +32,767(5-digt numbers). To store 5-digit numbers in USAGE DISPLAY format, you need PIC S9(05) and not PIC S9(04). Therefore, system decides in favour of PIC S9(05). And, therefore, when this (temporary) PIC S9(05) is displayed that is holding ‘00172’, you see ‘00172’.Had your variable been declared as PIC S9(N) COMP – N between 5 and 9, your display (on the variable) would have shown you ‘0000000172’, which means 10-digits. It is because PIC S9(6) COMP can hold some 10-digit numbers also(when compiled with TRUNC(BIN)). So, PIC S9(6) COMP temporarily converts to PIC S9(10).Q. A value of 555 is moved to PIC S9(02)V9 COMP and displayed. TRUNC(BIN) is used during compilation. What will be displayed? Will the display change if TRUNC(STD) is used? If yes, what is the new value displayed?A. PIC S9(02)V9 COMP occupies 2 bytes. We know that PIC S9(04) COMP can hold -32768 thru 32767. Here, PIC S9(02)V9 COMP has a range in such a way that after decimal sign, a maximum of one decimal digit is permitted. So, its range is -3276.8 thru 3276.7. Which means it can easily store 555. During DISPLAY, ‘COMP’ is temporarily dropped. And, similar to as PIC S9(03) COMP or PIC S9(04) COMP will display, here also, display will be ‘00555’.Section 10: Practice Questions True or False – TRUNC(BIN) makes COMP fields to accept values as per their binary limits.True or False – TRUNC(STD) makes COMP fields to behave like USAGE DISPLAY fields, as regards what values they can accept. ARITH(COMPAT) is used for compiling the program. What is the maximum value that PIC 9(06) can hold? Does this maximum value depend upon whether TRUNC(BIN) or TRUNC(STD) is used?ARITH(COMPAT) is used for compiling the program. What is the maximum value that PIC 9(06) COMP can hold? Does this maximum value depend upon whether TRUNC(BIN) or TRUNC(STD) is used?Memory size of PIC 9(4) COMP can be varied by compiler options in TRUNC? True or False.Memory size of PIC S9(6) COMP can be varied by compiler options in TRUNC? True or False.01 WS-HOURS-WORKED PIC 9(3) COMP. Program is compiled with ARITH(COMPAT), TRUNC(BIN). Fill the following table.Decimal Value movedDecimal value acceptedHexadecimal representation147??56??8788??34000??55555??82310??247??87??8000??35672??89100??Change the option to TRUNC(STD). Fill the table again. Comment on the differences, if any, you observe, between using two TRUNC options.01 WS-HOURS-WORKED PIC S9(3) COMP. Program is compiled with ARITH(COMPAT), TRUNC(BIN). Fill the following table.Decimal Value movedDecimal value acceptedHexadecimal representation147??56??8788??34000??55555??82310??247??87??8000??35672??89100??-147??-56??-8788??-34000??-55555??-82310??-247??-87??-8000??-35672??-89100??Change the option to TRUNC(STD). Fill the table again. Comment on the differences, if any, you observe, between using two TRUNC options.01 WS-HOURS-WORKED PIC S9(3) COMP. Fill the following table.Decimal Value movedDecimal value accepted (TRUNC(BIN))Decimal value accepted (TRUNC(STD))148??81??912??34000??55555??82310??247??35672??89100??-148??-81??-912??-34000??-55555??-82310??-247??-35672??-89100?? It is intended to store a 5 digit number in a numeric field. Which numeric data type(COMP, COMP-3, USAGE DISPLAY) requires least number of bytes? Give the PICTURE definition. What are the values of ARITH and TRUNC options when least number of bytes are used?In the context of data movement to a numeric variable of type COMP, does truncation mean same as conversion?During HEX ON on a file opened in view mode, following value is seen. It is known to be a numeric field(without decimal)8000What can be the data type for this field? Give all possible variable declarations to get this value. Give reasons for your answer.During HEX ON on a file opened in view mode, following value is seen. It is known to be a numeric field(without decimal)7GAFComment on possible variable declarations and corresponding decimal data in it.During HEX ON on a file opened in view mode, can a COMP field show ‘H’ anywhere in the data? What are valid characters for COMP field in HEX ON mode?During HEX ON on a file opened in view mode, can a COMP-3 field show ‘H’ anywhere in the data? What are valid characters for COMP-3 field in HEX ON mode?During HEX ON on a file opened in view mode, following value is seen. It is known to be a numeric field(without decimal)123FComment on possible variable declarations and corresponding decimal data in it.During HEX ON on a file opened in view mode, following value is seen in a COMP field(without decimal)8127Comment on possible variable declarations and corresponding decimal data in it.What is the range of values that PIC 9(4) COMP has?What is the range of values that PIC S9(4) COMP has?How many digits are displayed in SYSOUT when a DISPLAY statement is made on a PIC S9(7) field?How many digits are displayed in SYSOUT when a DISPLAY statement is made on a PIC S9(7) COMP field?How many bytes are occupied by PIC S9(5) COMP? Does number of bytes used dependent on any compiler settings of ARITH and BIN?True or False - ARITH(EXTEND) is used to make COMP fields accept more than 18 digits of data.True or False - Using ARITH(EXTEND), PIC S9(09) COMP can accept 15 digits numbers.True or False - ARITH(EXTEND) is used. If TRUNC(BIN) is used, then PIC S9(18) COMP can accept numbers limited by binary limit. Whereas if TRUNC(STD) is used, then PIC S9(18) COMP can accept standard(max 18 digits) of numbers.PIC S9(04) COMP is used. Can HEX ON show 8000FF FFFor any data value? If yes, for what value?PIC 9(04) COMP is used. Can HEX ON show 8000FF FFFor any data value? If yes, for what value?COMP variable is being used and TRUNC(BIN) option is in effect. What will be the least hexadecimal value in the leftmost nibble value when a negative number(permitted by the binary boundary) is stored in it.ARITH(COMPAT), TRUNC(BIN) is being used for compilation. Can a 19-digit PICTURE clause be declared?TRUNC(STD) is being used. How many digits will be displayed by PIC S9(5) COMP field?01 WS-ROI PIC S9(01)V99 COMP.01 WS-PRINCIPAL PIC 9(05)V99.01 WS-INTEREST PIC 9(05)V99.MOVE 12345 TO WS-PRINCIPALMOVE 12 TO WS-PUTE WS-INTEREST = (WS-PRINCIPAL * WS-ROI) / 100.DISPLAY WS-INTERESTWhat will be the display if TRUNC(BIN) is used?What will be the display if TRUNC(STD) is used?See the display if default values are supplied to TRUNC.A COMP field is used as a file variable. Data in the variable is displayed using DISPLAY. Also, it is viewed using HEX ON and converted to decimal using calculator. For which TRUNC option(between BIN or STD), can the two methods give different values? Can this behavior be exhibited by unsigned COMP fields?PIC S9(03) COMP is used for a file variable. TRUNC(BIN) is used. A value -32770 is intended to be stored using a MOVE statement. What is the decimal value accepted by the variable? What value does DISPLAY show? What hexadecimal value does variable show when HEX ON is done on the file?A job that is part of a batch job calculates claim amount payable for claims filed and approved for payment. A deductible field is present in the claim settlement file of this job. This field is calculated by the program. Deductible field is defined as PIC S9(3) COMP. An arithmetic statement computes a value and moves into this field. If the value moved is123, 456, 31012, 40126What will be the amounts moved to this field in each of above cases? (You can assume that program is compiled with ARITH(COMPAT), TRUNC(BIN).What will the hexadecimal values shown by this field in each of above cases.From the above values, if there are any that do NOT get moved as it is, to the COMP field, can compiler options be tweaked suitably so they get accepted by the COMP variable as it is?PIC S9(08) COMP is used for a file variable. Program is compiled with ARITH(COMPAT), TRUNC(STD). Multiplication is carried out between following variables and output is stored in the COMP field.01 WS-NUMBER-OF-PEOPLE PIC 9(7).01 WS-AVERAGE-SALARY PIC 9(5).Is COMP field capable to store the result of multiplication? If yes, why? If no, why?What is the maximum value storable in COMP field?What should be the minimum size of COMP field to be able to accept all results possible from multiplication?If we do not wish to reduce the size of COMP field, and realize that size of WS-NUMBER-OF-PEOPLE is reducible, then what should be the reduced size of WS-NUMBER-OF-PEOPLE chosen?If program was complied with ARITH(COMPAT), TRUNC(STD), what is the maximum storable value in the COMP field? ................
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