The isalnum() function in C use to checks given argument is an alphanumeric character (alphabet or number) or not.
Syntax : -
int isalnum(int argument);
This function is define in ctype.h header file.
Return Value For isalnum() function in c
it return 1 if given argument in program is an alphanumeric character.
isalnum() function return 0 if given argument in program is not an alphabet or a digit.
Example program for isalnum() function in c
#include <stdio.h>
#include <ctype.h>
int main()
{
char c;
int result;
c = '5';
result = isalnum(c);
printf("When %c is passed, return value is %d\n", c, result);
c = 'Q';
result = isalnum(c);
printf("When %c is passed, return value is %d\n", c, result);
c = 'l';
result = isalnum(c);
printf("When %c is passed, return value is %d\n", c, result);
c = '+';
result = isalnum(c);
printf("When %c is passed, return value is %d\n", c, result);
return 0;
}
Output of Program
- When 5 is passed, return value is 1
- When Q is passed, return value is 1
- When l is passed, return value is 1
- When + is passed, return value is 0