Prata exs 9.7

#include <stdio.h>
#include <ctype.h>

int func1(char);
int main()
{
    char ch;
    int result;

    while((ch = getchar())!= EOF)
    {
        result =func1(ch);
        printf("result is %d\n",result);

    }

    return 0;
}

int func1(char c)
{
    int res;
    if(islower(c))
    {
        res = c - 'a'+1;
    }
    else if(isupper(c))
    {
        res = c - 'A'+1;
    }
    else
        res = -1;
    return res;
}