main.c

#include <stdio.h>
#include "str.h"

int main(int argc, char *argv[])
{
    char *str = "this is a test!";

    printf("%s\n", my_strchr(str, 'a'));


    char *substr = my_substr(str, 0, 9);
    printf("%s\n", substr);
    free(substr);

    printf("%s\n", my_strstr(str, "test"));
    printf("%s\n", my_strstr(str, "this"));

    char *notfound = my_strstr(str, "unexistent");

    if(notfound != NULL){
        printf("%s\n", notfound);
    }

    return 0;
}