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

void f(const char s[], char *ext) {
    uint i = 0;
    while (s[i] != 0) {
        char c = s[i];
        ext[i] = c + ((c >= 65 && c <= 90) * 32) - ((c >= 97 && c <= 122) * 32);
        i++;
    }
    ext[i] = 0;
}

int main() {
    char s[256];
    char s1[] = "baab";
    char s2[] = "kayak";
    char s3[] = "Hello Word!";
    f(s1, s);
    printf("f(\"%s\") = \"%s\"\n", s1, s);
    f(s2, s);
    printf("f(\"%s\") = \"%s\"\n", s2, s);
    f(s3, s);
    printf("f(\"%s\") = \"%s\"\n", s3, s);
}