Programming in C

Programming in C

switch statement

switch( expression ) { case constant1: statement ... break; case constant2: statement ... break;

... default:

statement ... break; }

Example: A simple calculator.

#include

int number; char type; char line[80];

int main( void ) {

while(1) {

printf( "Enter conversion and number: "); fgets(line, sizeof(line), stdin); sscanf( line, "%c", &type );

if ((type == 'q') || (type == 'Q')) break;

switch (type) { case 'o': case 'O': sscanf(line, "%c %o", &type, &number); break;

October1, 2014

case 'x': case 'X':

sscanf(line, "%c %x", &type, &number); break; case 'd': case 'D': sscanf(line, "%c %d", &type, &number); break; case '?': case 'h': case 'H': printf( "Letter Conversion:\n"); printf(" o Octal\n"); printf(" x Hexadecimal\n"); printf(" d Decimal\n"); printf(" q Quit program\n");

continue;

default:

printf(" Type ? or h for help\n");

continue;

}

/* End of switch */

printf("Result is %d\n", number);

}

/* End of while */

return 0; }

MISC:

1) How to convert a number to a string.

int sprintf ( char *s, const char *format, ... ) sprintf takes three arguments.

The first has to be a char * variable, which means you can use a char array, but make sure it's big enough to hold the converted number.

The second argument is a string containing a format specifier, depending on the format of the number you want to convert.

The third argument is the number you want to convert into a string.

sprintf returns the number of characters in the string (not included the null character).

2) How to convert a string to a number:

double atof( const char *str) int atoi( const char *str )

They are in stdlib.h header.

3) How to generate random numbers in C:

#include rand();

Examples: ran.c, ran01.c, ran1.c

/* ran.c Shifted, scaled integers produced by 1 + rand() % 6 */

#include #include

int main() {

int i;

for ( i = 1; i ................
................

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