isalnum in c

1#include <stdio.h>
2#include <ctype.h>
3int main()
4{
5    char c;
6    int result;
7
8    c = '5';
9    result = isalnum(c);
10    printf("When %c is passed, return value is %d\n", c, result);
11
12    c = 'Q';
13    result = isalnum(c);
14    printf("When %c is passed, return value is %d\n", c, result);
15
16    c = 'l';
17    result = isalnum(c);
18    printf("When %c is passed, return value is %d\n", c, result);
19
20    c = '+';
21    result = isalnum(c);
22    printf("When %c is passed, return value is %d\n", c, result);
23
24    return 0;
25}
26