C/Macro Preprocessor/Preprocessor

#include <stdio.h>
/* define CHAR_SET as either 256 or 128 */
#define CHAR_SET 256
int main(void)
{
  int i;
  
#if CHAR_SET == 256
  printf("Displaying full ASCII character set plus extensions.\n");
#else
  printf("Displaying only ASCII character set.\n");
#endif
  for(i = 0; i < CHAR_SET; i++)
    printf("%c", i);
  return 0;
}