第8周任务2（定义各种重载运算符）

喜欢ヅ旅行 2022-06-13 10:51 154阅读 0赞

/* (程序头部注释开始)
    * 程序的版权和版本声明部分
    * Copyright (c) 2011, 烟台大学计算机学院学生 
    * All rights reserved.
    * 文件名称：                              
    * 作    者：   臧鹏               
    * 完成日期：   2012   年  4 月 9  日
    * 版 本 号：          
    
    * 对任务及求解方法的描述部分
    * 输入描述：
    * 问题描述：定义各种运算符
    * 程序输出： 
    * 程序头部的注释结束
    */
    #include <iostream>
    using namespace std;
    class CTime
    {
    private:
    	unsigned short int hour;    // 时
    	unsigned short int minute;  // 分
    	unsigned short int second;  // 秒
    public:
    	CTime(int h=0,int m=0,int s=0):hour(h), minute(m), second(s){}  ;
    	void setTime(int h,int m,int s);
    	void display();
    	//比较运算符(二目)的重载
    	bool operator > (CTime &t);
    	bool operator < (CTime &t);
    	bool operator >= (CTime &t);
    	bool operator <= (CTime &t);
    	bool operator == (CTime &t);
    	bool operator != (CTime &t);
    	//二目运算符的重载
    	CTime operator+(CTime &c);//返回c所规定的时、分、秒后的时间，例t1(8,20,25),t2(11,20,50)，t1+t2为:41:15
    	CTime operator-(CTime &c);//对照+理解
    	CTime operator+(int s);//返回s秒后的时间
    	CTime operator-(int s);//返回s秒前的时间
    	//一目运算符的重载
    	CTime operator++(int);//后置++，下一秒
    	CTime operator++();//前置++，下一秒
    	CTime operator--(int);//后置--，前一秒
    	CTime operator--();//前置--，前一秒
    	//赋值运算符的重载     
    	CTime operator+=(CTime &c);
    	CTime operator-=(CTime &c);
    	CTime operator+=(int s);//返回s秒后的时间
    	CTime operator-=(int s);//返回s秒前的时间
    };
    //下面实现所有的运算符重载代码。
    //为简化编程，请注意通过调用已有函数，利用好各函数之间的关系
    void CTime::setTime(int h,int m,int s)
    {
    	hour = h;
    	minute = m;
    	second = s;
    }
    void CTime::display()//显示函数
    {
    	cout<< hour << ":" << minute << ":"  << second << endl;
    }
    
    bool CTime::operator > (CTime &t)//大于比较符（把时间都化成秒进行比较要容易得多，下同）
    {
    	if(hour*3600+minute*60+second >t.hour*3600+t.minute*60+t.second)
    	{
    		return true;
    	}
    	else
    		return false;
    }
    bool CTime::operator < (CTime &t)//小于比较符
    {
    	if(hour*3600+minute*60+second <t.hour*3600+t.minute*60+t.second)
    	{
    		return true;
    	}
    	else
    		return false;
    }
    bool CTime::operator >= (CTime &t)//大于等于比较符
    {
    	if(hour*3600+minute*60+second >= t.hour*3600+t.minute*60+t.second)
    	{
    		return true;
    	}
    	else
    		return false;
    }
    bool CTime::operator <= (CTime &t)//小于等于比较符
    {
    	if(hour*3600+minute*60+second <= t.hour*3600+t.minute*60+t.second)
    	{
    		return true;
    	}
    	else
    		return false;
    }
    bool CTime::operator == (CTime &t)//等于比较符
    {
    	if(hour == t.hour && minute == t.minute && second == t.second)
    	{
    		return true;
    	}
    	else
    		return false;
    }
    bool CTime::operator != (CTime &t)//不等于
    {
    	if(hour != t.hour ||minute != t.minute || second != t.second)
    	{
    		return true;
    	}
    	else
    		return false;
    }
    //二目运算符的重载
    CTime CTime::operator+(CTime &t)//返回c所规定的时、分、秒后的时间，例t1(8,20,25),t2(11,20,50)，t1+t2为:41:15
    {
    	CTime t1;
    	int time;
    	time = hour*3600+minute*60+second+t.hour*3600+t.minute*60+t.second;//利用中间变量，把时间都化成秒在进行运算，再化成时分秒，下同
    	t1.hour=time/3600;
    	time =time%3600;
    	t1.minute =time/60;
    	time = time%60;
    	t1.second =time;
    	return t1;
    }
    
    CTime CTime::operator-(CTime &t)//对照+理解
    {
    	CTime t1;
    	int time;
    	time = hour*3600+minute*60+second-(t.hour*3600+t.minute*60+t.second);
    	if(time<0)
    	{
    		time = -time;
    	}
    	t1.hour=time/3600;
    	time =time%3600;
    	t1.minute =time/60;
    	time = time%60;
    	t1.second =time;
    	return t1;
    }
    CTime CTime::operator+(int s)//返回s秒后的时间
    {
    	CTime t0;//利用一个中间变量是防止函数把this指针所指向的这个对象改变，此处不能用const，否则运行函数无效
    	int time = hour * 3600 + minute * 60 + second + s; 
    
    	t0.hour = time / 3600; 
    
    	time = time % 3600; 
    
    	t0.minute = time / 60; 
    
    	time = time % 60; 
    
    	t0.second = time;   
    
    	return t0; //返回中间变量，如果返回（*this）则下个函数的默认对象就为这个函数所改变后的对象
    }
    CTime CTime::operator-(int s)//返回s秒前的时间
    {
    	CTime t0;
    
    	int time = hour * 3600 + minute * 60 + second-s;   
    
    	t0.hour = time / 3600; 
    
    	time = time % 3600; 
    
    	t0.minute = time / 60; 
    
    	time = time % 60; 
    
    	t0.second = time; 
    
    	return t0; 
    }
    //一目运算符的重载
    CTime CTime::operator++(int)//后置++，下一秒
    {
    	CTime temp(*this);//提前保存this指针所指向的这个对象
    	{
    		second++;
    		if(second>=60)
    		{
    			second-=60;
    			++minute;
    			if(minute>=60)
    			{
    				minute-=60;
    				++hour;
    			}
    		}
    
    	}
    	return temp;//返回的对象为改之前的，但实际对象已经改变了
    }
    CTime CTime::operator++()//前置++，下一秒
    {
    	if(++second>=60)
    	{
    		second-=60;
    		++minute;
    		if(minute>=60)//注意分钟也可能越界
    		{
    			minute-=60;
    			++hour;
    		}
    	}
    	return (*this);
    }
    CTime CTime::operator--(int)//后置--，前一秒
    {
    	CTime temp(*this);
    	second--;
    	if(second<0)//秒被减成负的那么要考虑分钟减一。秒数为60-second
    	{   
    		second = 60+second;
    		--minute;
    		if(minute<0)
    		{
    			--hour;
    		}
    	}
    	return temp;
    }
    CTime CTime::operator--()//前置--，前一秒
    {
    	if(--second<0)
    	{
    		second =60+second;
    		--minute;
    		if(minute<0)
    		{
    			--hour;
    		}
    	}
    	return (*this);
    }
    //赋值运算符的重载     
    CTime CTime::operator+=(CTime &t)
    {
    	int time;
    	time = hour*3600+minute*60+second+t.hour*3600+t.minute*60+t.second;
    	hour = time/3600;
    	if(hour>=24)//如果小时大于24，自动归零
    	{
    		hour-=24;
    	}
    	time = time%3600;
    	minute = time/60;
    	time = time%60;
    	second = time;
    	return  (*this);
    }
    CTime CTime::operator-=(CTime &t)
    {
    	int time;
    	time = hour*3600+minute*60+second-(t.hour*3600+t.minute*60+t.second);
    	if (time<0)
    	{
    		time = -time;
    	}
    	hour = time/3600;
    	if(hour>=24)
    	{
    		hour-=24;
    	}
    	time = time%3600;
    	minute = time/60;
    	time = time%60;
    	second = time;
    	return  (*this);
    }
    CTime CTime::operator+=(int s)//返回s秒后的时间
    {
    
    	second+=s;
    	if(second>=60)
    	{
    		minute+=second/60;
    		second = second%60;
    	}
    	if(minute>=60)
    	{
    		hour+=minute/60;
    		minute=minute%60;
    	}
    	if(hour>=24)
    	{
    		hour = hour%24;
    	}
    	return  (*this);
    }
    CTime CTime::operator-=(int s)//返回s秒前的时间
    {
    	int time;
    	time = hour*3600+minute*60+second-s;
    	if(time<0)
    	{
    		time = -time;
    	}
    	else
    		hour = time/3600;
    	time = time%3600;
    	minute = time/60;
    	time = time%60;
    	second = time;
    	return (*this);
    }
    
    
    void main()
    {
    	CTime t1(8,20,25),t2(11,20,50),t;
    	cout<<"t1为：";
    	t1.display();
    	cout<<"t2为：";
    	t2.display();
    	cout<<"下面比较两个时间大小：\n";
    	if (t1>t2) cout<<"t1>t2"<<endl;
    	if (t1<t2) cout<<"t1<t2"<<endl;
    	if (t1==t2) cout<<"t1＝t2"<<endl; 
    	if (t1!=t2) cout<<"t1≠t2"<<endl;
    	if (t1>=t2) cout<<"t1≥t2"<<endl;
    	if (t1<=t2) cout<<"t1≤t2"<<endl;
    	cout<<endl;
    	//下面自行设计对其他运算符的重载的测试
    	t = t1+t2;
    	cout<<"t1+t2 =";
    	t.display();
    
    	t = t1-t2;
    	cout<<"t1-t2 =";
    	t.display();
    
    	t = t1+15;
    	cout<<"t1+15s =";
    	t.display();
    
    	t = t1-15;
    	cout<<"t1-15s =";
    	t.display();
    
    	t = t1++;
    	cout<<"t1++ =";
    	t.display();
    
    	t = ++t1;
    	cout<<"++t1 =";
    	t.display();
    
    	t = t1--;
    	cout<<"t1-- =";
    	t.display();
    
    	t = --t1;
    	cout<<"--t1 =";
    	t.display();
    	t1+=t2;
    	cout<<"t1+=t2  =";
    	t1.display();
    	t1-=t2;
    	cout<<"t1-=t2  =";
    	t1.display();
    	t1 +=124;
    	cout<<"t1+=124s =";
    	t1.display();
    	t1 -=555;
    	cout<<"t1-=555s =";
    	t1.display();
    	system("pause");
    
    
    }

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经验积累：

每个成员函数都可能改变当前对象的值，所以要想后面的函数不受影响，可以用中间变量的方法，进行运算，返回那个中间变量，这样就使后面的函数不受影响了，再就是对时间的处理上要注意越界的情况，进还是退，要有相关的机制来应对。再就是程序虽长但是要细心和有耐心。

[1333979842_2134.png]: https://img-my.csdn.net/uploads/201204/09/1333979842_2134.png