tst_isalnum.c

KEILC51程序实例和配套硬件目标板,很详细,程序有注释

#include <ctype.h>
#include <stdio.h>           /* for printf */
void tst_isalnum (void) {
  unsigned char i;
  char *p;
    for (i = 0; i < 128; i++) {
      p = (isalnum (i) ? "YES" : "NO");
      printf ("isalnum (%c) %s\n", i, p);
    }
}