Language Ccpp Cref Examples Macro.c

/ ****************************************************************
 *
 * Purpose: To demonstrate macros
 * Author:  M.J. Leslie
 * Date:    17-Oct-94
 *
 ****************************************************************/

#define SQUARE(x) ( (x)*(x) )

main()
{
  int value=3;

  printf("%d \n", SQUARE(value));
}
/****************************************************************
 *
 * answer will be 9
 *
 ****************************************************************/

	-------------------------------------------------


// Another common macro to compute the absolute value.
#define absolute_value( x ) ( ((x) < 0) ? -(x) : (x) )

// and here is a sample useage...
int x = -1;
while( absolute_value( x ) ) {
// ...
  }       


	-------------------------------------------------

//a general purpose incrementing "for" loop
#define count_up( v, low, high ) \
	for( (v) = (low); (v) <= (high); (v)++ )          

//prints out the integers 1 through 20:
int i;
count_up( i, 1, 20 ) {
	printf( "i is %d\n", i );
	}