Method setBorn

week09/examples/firstclass.cpp:21–27

        name[len] = '\0';
    }
    void setBorn(int b)
    {
        if (b >= 1990 && b <= 2020 )
            born = b;
        else
            std::cerr << "The input b is " << b << ", and should be in [1990, 2020]." << std::endl;
    }
    void setGender(bool isMale)
    {
        male = isMale;