cmp

bool cmp(char a, char b)
{
    if (((a>='A' && a<='Z') && (b>='A' && b<='Z'))|| ((a>='a' && a<='z') and (b>='a' and b<='z')))
        return a<b;
    else {
        if ((a>='A' && a<='Z') && (b>='a' && b<='z')) {
            int x=a-'A', y=-'a';
            return x<y;
        }
        else if ((a>='a' && a<='z') && (b>='A' && b<='Z')) {
            int x=a-'a', y=-'A';
            return x<y;
        }
    }
}