int truncate(char *s, int n){
    int len = strlen(s);
    printf("%d", len);
    if (len <= n){
        return 0;
    }
    else{
        s[n] = '\0';
        return (len-n);
    }
}
    Write a function named truncate() that takes a string s and a
    non-negative integer n. If s has more than n characters (not including the
    null terminator), the function should truncate s at n characters and
    return the number of characters that were removed. If s has n or
    fewer characters, s is unchanged and the function returns 0. For example,
    if s is the string "function" and n is 3, then truncate() changes s to
    the string "fun" and returns 5.