#include <stdio.h>

char *strchr(const char *str, int c) {
    for ( ; *str; str++) {
        if (*str==c) {
            return (char *)str;
        }
    }
    return NULL;
}


int main(void) {
    char *ptr;
    char fox[] = "The quick brown fox jumps over the lazy dog.";

    ptr = strchr(fox, 'z');
    if (ptr) {
        printf("%s\n", ptr);
    }

    return 0; 
}