《第九周任务二》定义Time类中的<<和>>运算符的重载，实现时间输入输出，改造源程序中对运算结果的显示方式，使程序读起来更自然

/*

* 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：  张斌                           

* 完成日期：  2012年 4 月 16 日

* 版 本 号： 9-2-1        

* 对任务及求解方法的描述部分

* 代码实现

#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){ }

//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

friend ostream& operator << (ostream&,CTime&);
friend istream& operator >> (istream&,CTime&);
};
//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

ostream& operator << (ostream&output,CTime&t)
{
output << t.hour << ":" << t.minute<< ":" << t.second;

return output;
}

istream& operator >> (istream&input,CTime&t)
{
cout << "请输入合法的时间：例（23：12：25）";

char a;

do
{
input >> t.hour >> a >> t.minute >> a >> t.second;
}

while(a != ':' || t.hour > 24 || t.minute >60 || t.second >60);

return input;
}

bool CTime::operator > (CTime &t)//转换为秒，在进行比较。
{
if(hour * 3600 + minute * 60 + second > t.hour * 3600 + t.minute * 60 + t.second)
{
return true;
}
else
{
return false;
}
}

bool CTime::operator < (CTime &t)
{
if(hour * 3600 + minute * 60 + second < t.hour * 3600 + t.minute * 60 + t.second)
{
return true;
}
else
{
return false;
}
}

bool CTime::operator >= (CTime &t)
{
if(hour * 3600 + minute * 60 + second >= t.hour * 3600 + t.minute * 60 + t.second)
{
return true;
}
else
{
return false;
}
}
bool CTime::operator <= (CTime &t)
{
if(hour * 3600 + minute * 60 + second <= t.hour * 3600 + t.minute * 60 + t.second)
{
return true;
}
else
{
return false;
}
}
bool CTime::operator == (CTime &t)//小时，分钟，秒数都相同
{
if(hour == t.hour && minute == t.minute && second == t.second)
{
return true;
}
else
{
return false;
}
}
bool CTime::operator != (CTime &t)//小时，分钟，秒数有一个不同即可
{
if(hour != t.hour || minute != t.minute || second != t.second)
{
return true;
}

else
{
return false;
}
}

CTime CTime::operator + (CTime &c)
{
CTime c2;
int time;
//现将两个时间转化为秒，再依次求出小时，分，秒即可。
time = (hour * 3600 + minute * 60 + second) + (c.hour * 3600 + c.minute * 60 + c.second);

c2.hour = time / 3600;

time = time % 3600;

c2.minute = time / 60;

time = time % 60;

c2.second = time;

return c2;
}
CTime CTime::operator - (CTime &c)
{
CTime c2;
int time;
//现将两个时间转化为秒，再依次求出小时，分，秒即可。
time = (hour * 3600 + minute * 60 + second) - (c.hour * 3600 + c.minute * 60 + c.second);

c2.hour = time / 3600;

time = time % 3600;

c2.minute = time / 60;

time = time % 60;

c2.second = time;

return c2;
}

CTime CTime::operator + (int s)
{
int time;

time = hour * 3600 + minute * 60 + second + s;

hour = time / 3600;

time = time % 3600;

minute = time / 60;

time = time % 60;

second = time;

return (*this);
}

CTime CTime::operator - (int s)
{
int time;

time = hour * 3600 + minute * 60 + second;

time = time - s;

hour = time / 3600;

time = time % 3600;

minute = time / 60;

time = time % 60;

second = time;

return (*this);
}

CTime CTime::operator ++ (int) //后置
{
CTime temp = (*this);

int time;

time = hour * 3600 + minute * 60 + second + 1;

hour = time / 3600;

time = time % 3600;

minute = time / 60;

time = time % 60;

second = time;

return temp;//返回自加前的对象
}

CTime CTime::operator ++ ()//前置
{
int time;

time = hour * 3600 + minute * 60 + second +1;

hour = time / 3600;

time = time % 3600;

minute = time / 60;

time = time % 60;

second = time;

return (*this);//返回自加后的当前对象
}
CTime CTime::operator -- (int)//后置
{
CTime temp = (*this);

int time;

time = hour * 3600 + minute * 60 + second - 1;

hour = time / 3600;

time = time % 3600;

minute = time / 60;

time = time % 60;

second = time;

return temp;//返回自减前的对象
}
CTime CTime::operator -- ()//前置
{
int time;

time = hour * 3600 + minute * 60 + second - 1;

hour = time / 3600;

time = time % 3600;

minute = time / 60;

time = time % 60;

second = time;

return (*this);//返回自减后的当前对象
}

CTime CTime::operator += (CTime &c)
{
CTime c2;

c2 = (*this) + c;//调用重载运算符，第一个+号

return c2;
}
CTime CTime::operator -= (CTime &c)
{
CTime c2;

c2 = (*this) - c;//调用重载运算符，第一个-号

return c2;
}
CTime CTime::operator += (int s)
{
CTime c2;

c2 = (*this) + s;//调用重载运算符，第2个+号

return c2;
}
CTime CTime::operator -= (int s)
{
CTime c2;

c2 = (*this) - s;//调用重载运算符，第2个-号

return c2;
}

void main()
{
CTime t1, t2, t3;

cin >> t1 >> t2;

cout << "t1为：" << t1 <<endl;

cout << "t2为：" << t2 <<endl;

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;

t3 = t1 + t2;

cout << "t1 + t2 =" << t3 << endl;

t3 = t2 - t1;

cout << "t2 - t1 =" << t3 << endl;

t3 = t1;

t3 = t3 + 40;

cout << "t1 + 40s =" << t3 << endl;

t3 = t2;

t3 = t3 - 10;

cout << "t2 - 10s =" << t3 << endl;

t3 = t1++;

cout << "t1++ =" << t3 << endl;

t3 = --t2;

cout << "--t2 =" << t3 <<endl;

t3 = t1;

t3 += t2;

cout << "t1 += t2 , t1 = " << t3 << endl;

t3 = t2;

t3 -= 5;

cout << "t2 -= 5, t2 = " << t3 << endl;

system("pause");
}