设计一个 c++钟表类 延伸出时分秒类 时分秒数量表示数值

要求至少完成以下功能：
1.类，构造函数，析构函数，输出函数
2.封装，继承和多态

3.难度不能太简单
 

#include <iostream>

using namespace std;

class Clock
{
private:
	int hour, minute, second;
public:
	Clock();     //默认构造函数 
	Clock(int Newh, int Newm, int News);     // 构造函数 
	Clock(Clock &c);     //拷贝构造函数 
	~Clock() {cout << "正在析构对象\n";}
	void showtime();
};

int main()
{
	Clock myclock;
	cout << "myclock:" << endl;
	myclock.showtime();
	cout << "yourclock：" << endl;
	Clock yourclock(8, 16, 16);
	yourclock.showtime();
	cout << "otherclock:" << endl;
	Clock otherclock(yourclock);
	otherclock.showtime();
	
	return 0;	
} 

Clock::Clock()
{
	cout << "正在默认构造对象" << endl; 
	hour = 12; minute = 30; second = 30;	
}
Clock::Clock(int Newh, int Newm, int News)
{
	cout << "正在构造对象" << endl; 
	hour = Newh;
	minute = Newm;
	second = News;
}
Clock::Clock(Clock &c)
{
	cout << "正在复制构造对象" << endl;
	hour = c.hour;
	minute = c.minute;
	second = c.second;
}
void Clock::showtime()
{
	cout << hour << ":" <<minute << ":" << second << endl; 
}