C language determines whether characters are letters or numbers

// check if char is a  alphabet or digit in C language

#include <stdio.h>
#include <stdlib.h>

int main()
{
    char ch = 'i';
    if( (ch >='0'  && ch <= '9') || (ch >='a'  && ch <= 'z') || (ch >='A'  && ch <= 'Z') ){
        printf("the char is a digit or alphabet");
    }

    return 0;
}