Regular expression matching

bool isMatch(char* s, char* p) {
    if (*p == '\0') {
        return *s == '\0';
    }

    bool first_match = *s && (*s == *p || *p == '.');

    if (*(p + 1) == '*') {
        return isMatch(s, p + 2) || (first_match && isMatch(s + 1, p));
    } else {
        return first_match && isMatch(s + 1, p + 1);
    }
}