Program to change the case of alphabet

#include<stdio.h>
int main()
{
        char a;
        int b;
        printf(" \n enter the alphabet from the keyboard " );
        scanf("%c" ,&a);

        b=a;
        if(b >= 97 && b <=122)
        {
                b=b-32;
        }
        printf("%c", b);
}