1 - Vocational Training Council



Assignment1 Answer(More than the assignment needed!!)

|1. | |Suppose a and b are int variables. What is the value of b? |

| | |a = 3; |

| | |b = 4 + (++a); |

| | |Answer: 8 |

|2. | |Given the following assignments. What is the value in str? |

| | |String str; |

| | |str = “Hello”; |

| | |str = str + “ World”; |

| | |Answer: Hello World |

|3. | |The method showInputDialog belongs to the class ____. |

| | |Answer: JOptionPane |

|4. | |The tokens of a string are usually delimited by ____ characters. |

| | |Answer: whitespace |

|5. | |What is the value of the expression: (10 >= 5) && (‘B’ < ‘C’) |

| | |Answer: true |

|6. | |With short-circuit evaluation, when the value of an entire expression is found, evaluation ____. |

| | |Answer: stops |

|7. | |Write a Java statement to accomplish each of the following tasks |

| | |a) Declare variables x, y, z, thisIsAVariable, q76354 and number to be of type int |

| | |Answer: |

| | |int x, y, z, thisIsAVariable, q76354, number; |

| | |b) Declare the variables xVal, yVal and zVal to be of type String. |

| | |Answer: |

| | |String xVal, yVal, zVal; |

| | |c) Convert xVal to an int and store the result in the variable x |

| | |Answer: |

| | |x = Integer.parseInt(xVal); |

|8. | |Rewrite the following if-else statement using switch statement. [16 marks] |

| | | |

| | |if (florida == 1) { |

| | |System.out.println("Number 1 Ranking!"); |

| | |} |

| | |else if(florida == 2) { |

| | |System.out.println("Almost there ..."); |

| | |} |

| | |else { |

| | |System.out.println("Unacceptable"); |

| | |} |

| | | |

| | |Answer : |

| | |switch(florida) |

| | |{ |

| | |case 1: System.out.println("Number 1 Ranking!"); |

| | |break; |

| | |case 2: System.out.println("Almost there ... "); |

| | |break; |

| | |default: System.out.println("Unacceptable"); |

| | |} |

| | | |

|9. | |What is the result of running the following piece of code? |

| | |import java.util.*; |

| | |public class Test{ |

| | |public static void main(String args[]){ |

| | |String s = new String("Java~see~Java~do"); |

| | |StringTokenizer st = new StringTokenizer(s, "/"); |

| | |int count = 1; |

| | |while(st.hasMoreTokens()){ |

| | |System.out.println("Token number " + count + " : " + st.nextToken()); |

| | |count++; |

| | |} |

| | |} |

| | |} |

| | |Answer : |

| | |Java~see~Java~do |

|10 | |Assume that the way the StringTokenizer is created in the above sample program is changed as follows: |

| | |StringTokenizer st = new StringTokenizer(s, "~"); |

| | |What is the result of the sample program? |

| | |import java.util.*; |

| | |public class Test{ |

| | |public static void main(String args[]){ |

| | |String s = new String("Java~see~Java~do"); |

| | |StringTokenizer st = new StringTokenizer(s, "~"); |

| | |int count = 1; |

| | |while(st.hasMoreTokens()){ |

| | |System.out.println("Token number " + count + " : " + st.nextToken()); |

| | |count++; |

| | |} |

| | |} |

| | |} |

| | |Answer : |

| | |Token number 1 : Java |

| | |Token number 2 : see |

| | |Token number 3 : Java |

| | |Token number 4 : do |

|11 | |Rewrites the following program segment by using a while and a do … while loop to have the same output. |

| | |j = 2; |

| | |For(i = 1;i 4) || (j++ == 7)) is evaluated using short circuit. Because 8 > 4 is true, the expression (j++ == 7) is not |

| | |evaluate. Therefore, the value of j stays 0. On the other hand, to evaluate the expression ((8 > 4) | (j++ == 7)) no short circuit is |

| | |used. Therefore, both the expressions (8 > 4) and (j++ == 7)) are evaluated. The expression j++ increments the value j by 1. |

|13 | |Suppose that str is a String variable. Write a Java statement that uses the operator new to instantiate the object str and assign the |

| | |string “Java Programming” to str. |

| | |Ans: |

| | |str = new String (“Java Programming”) |

|14 | |Consider the following statements: |

| | |String str = “Going to the amusement park.”; |

| | |char ch; |

| | |int len; |

| | |int position; |

| | |What value is stored in ch by the following statement? |

| | |ch = str.charAt(0); |

| | |The value stored in ch is ‘G’. |

| | |What value is stored in ch by the following statement? |

| | |ch = str.charAt(11); |

| | |The value stored in ch is ‘e’. |

| | |What value is stored in len by the following statement? |

| | |len = str.length(); |

| | |The value stored in len is 28. |

| | |What value is stored in position by the following statement? |

| | |position = str.indexOf(‘t’); |

| | |The value stored in position is 6 |

| | | |

| | | |

|15 | |Rewrite the following decision statement using the conditional operator (?:). |

| | |If(page == odd) |

| | |System.out.println(“This is an odd page.”); |

| | |else |

| | |System.out.println(“This is an even page.”); (5 marks) |

| | |Ans: System.out.println(“This is an “ + (page==odd ? “odd” : “even ”) + “page.”); |

|16 | |Assume the following statements: |

| | | |

| | |String str; |

| | |String str1 = “diploma”; |

| | |String str2; |

| | |String str3; |

| | |str = “Java programming: second programming module for diploma courses”; |

| | | |

| | |What are the value of the following expressions? |

| | | |

| | |str.indexOf(“module”) |

| | |str.substring(5, 16); |

| | |str.startsWith(“Java”) |

| | |str.startsWith(“J”) |

| | |str.endsWith(“.”) |

| | |str.regionMatches(48, str1, 0, str1.length()); |

| | |str.regionMatches(true, 31, “module”, 0, 6); |

| | | |

| | |Note: the method header of regionMathces() are |

| | |Boolean regionMatches(int index, String str, int strIndex, int len); |

| | |Boolean regionMatches(boolean ignorcase, int index, String str, int strIndex, int len); |

| | |Ans: |

| | |(a) 37 |

| | |programming |

| | |true |

| | |true |

| | |false |

| | |true |

| | |false |

|17 | |What is the result of the following piece of code? |

| | |public class C8Q9{ |

| | |public static void main(String args[]){ |

| | |if( 3 > 4 | 4 > 1 | 1 == 0){ |

| | |System.out.println(" OR condition satisfied"); |

| | |} |

| | |else{ |

| | |System.out.println(" OR condition not satisfied"); |

| | |} |

| | |} |

| | |} |

| | |Ans: |

| | |OR condition satisfied |

|18 | |What is the output of the following piece of code? |

| | |public class C8Q3{ |

| | |public static void main(String args[]){ |

| | |int i = 100; |

| | |System.out.println("Result: " + (( i < 100 ) ? 20.8 : 10 )); |

| | |} |

| | |} |

| | |Result: 10.0 |

|19 | |The difference between char and Character is |

| | |Ans: |

| | |char is a primitive type; Character is a class |

| | | |

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