已有类Time和Date,要求设计一个 派生类Birthtime,它继承类Time和Date,并且增加一个数据成员Child name用于表示小孩的名字，同时设计主程序显示一个小孩的出生时间和名字。

以下是实现该要求的代码：

#include <iostream>
#include <string>
using namespace std;

class Time {
public:
    Time(int h = 0, int m = 0, int s = 0) {
        hour = h;
        minute = m;
        second = s;
    }
    void displayTime() const {
        cout << hour << ":" << minute << ":" << second;
    }
protected:
    int hour, minute, second;
};

class Date {
public:
    Date(int y = 0, int m = 0, int d = 0) {
        year = y;
        month = m;
        day = d;
    }
    void displayDate() const {
        cout << year << "-" << month << "-" << day;
    }
protected:
    int year, month, day;
};

class Birthtime : public Time, public Date {
public:
    Birthtime(int y = 0, int m = 0, int d = 0, int h = 0, int min = 0, int s = 0, const string& name = "") : Time(h, min, s), Date(y, m, d), childName(name) {}
    void display() const {
        cout << "Child's name: " << childName << endl;
        cout << "Birth date: ";
        displayDate();
        cout << endl;
        cout << "Birth time: ";
        displayTime();
        cout << endl;
    }
private:
    string childName;
};

int main() {
    Birthtime b(2022, 9, 18, 8, 30, 0, "Alice");
    b.display();
    return 0;
}

运行结果如下：

Child's name: Alice
Birth date: 2022-9-18
Birth time: 8:30:0