int truncate(char *s, int n)
{
    if (strlen(s) > n)
    {
        s[n] = '\0';
        return strlen(s) - n;
    }
    return 0;
}

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.