请各位支招，谢谢

class CBirthday
{
public:
    CBirthday(int year = 0,int month = 0,int day = 0)
    :m_iYear(year),m_iMonth(month),m_iDay(day)
    {

    }

    ~CBirthday(){}

    CBirthday(const CBirthday& birthday)
    {
        m_iYear = birthday.m_iYear;
        m_iMonth = birthday.m_iMonth;
        m_iDay = birthday.m_iDay;
    }

    void Show()
    {
        cout << m_iYear <<" "<< m_iMonth <<" "<< m_iDay <<endl;
    }

private:
    int m_iYear;
    int m_iMonth;
    int m_iDay;
};

class CStudent
{
public:
    CStudent(char name[20],int id,CBirthday birthday)
    {
        strcpy(this->name,name);
        this->id = id;
        this->birthday = birthday;
    }
    ~CStudent(){}
   
    CStudent(const CStudent& student)
    {
        strcpy(this->name,student.name);
        this->id = student.id;
        this->birthday = student.birthday;
    }

    void Show()
    {
        cout << name <<" " << id <<" ";
        birthday.Show();
    }

private:
    char name[20];
    int id;
    CBirthday birthday;
};
void main()
{
    CBirthday b(2000,1,1);
    CStudent s("Tom",1,b);
    b.Show();
    s.Show();

    getchar();
}