isalpha fonksiyonu 0dan

#include <stdio.h>
int myIsalpha(char plm){
    int yg=0;
    if(plm>='a'){
        if(plm<='z'){
            yg=1;
        }
    }
    else{
        if(plm<='9'){
            if(plm>='0'){
                yg=1;
            }
        }
    }
    return yg;
}
int main(){
    char yg=getchar();
    printf("%d\n",myIsalpha(yg));
    getchar();
}