第8周项目2-Time类中的运算符重载（续）

/*
*copyright (c)2015,烟台大学计算机学院
*All rights reserved
*文件名称：project.cpp
*作者：孙春红
*完成日期：2015年5月5日
*版本号：v1.0
*
*问题描述：在Time类中的运算符重载基础上
（1）定义对时间对象的自增和自减一目运算符。
（2）定义Time类中的<<和>>运算符重载，实现时间的输入输出，
改造原程序中对运算结果显示方式，使程序读起来更自然。
*输入描述：略。
*程序输出：略。
*/
#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);
    //二目的比较运算符重载
    bool operator > (CTime &t);
    bool operator < (CTime &t);
    bool operator >= (CTime &t);
    bool operator <= (CTime &t);
    bool operator == (CTime &t);
    bool operator != (CTime &t);
    //二目的加减运算符的重载
    //返回t规定的时、分、秒后的时间
    //例t1(8,20,25),t2(11,20,50)，t1+t2为19:41:15
    CTime operator+(CTime &t);
    CTime operator-(CTime &t);//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
    //二目赋值运算符的重载
    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
    CTime operator ++(int);
    CTime operator++();
    CTime operator--(int);
    CTime operator--();
    friend ostream& operator <<(ostream& output,CTime&t);
    friend istream& operator >>(istream& input,CTime&t);
};
void CTime::setTime(int h,int m,int s)
{
    hour=h;
    minute=m;
    second=s;
}
bool CTime::operator > (CTime &t)
{
    if (hour*60*60+minute*60+second>t.hour*3600+t.minute*60+t.second)
        return true;
    return false;
}

bool CTime::operator < (CTime &t)
{
    if (hour*60*60+minute*60+second<t.hour*3600+t.minute*60+t.second)
        return true;
    return false;
}
bool CTime::operator >= (CTime &t)
{
    if (*this < t) return false;
    return true;
}
bool CTime::operator <= (CTime &t)
{
    if (*this > t) return false;
    return true;
}//也可以如此：bool CTime::operator <= (CTime &t) {return !(*this > t)}
bool CTime::operator == (CTime &t)
{
    if (*this < t||*this >t) return false;
    return true;
}
bool CTime::operator != (CTime &t)
{
    if (*this == t) return false;
    return true;
}
CTime CTime::operator+(CTime &t)
{
    int h,m,s;
    s=second+t.second;
    m=minute+t.minute;
    h=hour+t.hour;
    if (s>59)
    {
        s%=60,
           m+=s/60;
    }
    if (m>59)
    {
        m%=60,
           h+=m/60;
    }
    if (h>23) h-=24;
    CTime ct(h,m,s);
    return ct;
}
CTime CTime::operator-(CTime &t)
{
    int h,m,s;
    s=second-t.second;
    m=minute-t.minute;
    h=hour-t.hour;
    if (s<0)
    {
        s+=60;
        m--;
    }
    if (m<0)
    {
        m+=60;
        h--;
    }
    if (h<0)
    {
        h+=24;
    }
    CTime ct(h,m,s);
    return ct;
}
CTime CTime::operator+(int s)//返回s秒后的时间
{

    second+=s;
    if(second>59)
    {
        second%=60,
                minute+=second/60;
    }
    if (minute>59)
    {
        minute%=60,
                hour+=minute/60;
    }
    if (hour>23)
    {
        hour-=24;
    }
    return *this;
}
CTime CTime::operator-(int s)
{
    int ss=s%60;
    int mm=(s/60)%60;
    int hh=s/3600;
    CTime t0(hh,mm,ss);
    return *this-t0;
}
CTime CTime::operator+=(CTime &c)
{
    *this=*this+c;
    return *this;
}
CTime CTime::operator-=(CTime &c)
{
    *this=*this-c;
    return *this;
}
CTime CTime::operator+=(int s)//返回s秒后的时间
{
    *this=*this +s;
    return *this;
}
CTime CTime::operator-=(int s)//返回s秒前的时间
{
    *this =*this-s;
    return *this;
}
ostream& operator <<(ostream& output,CTime&t)
{
    output<<t.hour<<":"<<t.minute<<":"<<t.second<<endl;
    return output;
}
istream& operator >>(istream& input,CTime&t)
{
    input>>t.hour>>t.minute>>t.second;
    return input;
}
CTime CTime::operator ++(int)
{
    CTime temp(*this);
    second++;
    if (second>=60)
    {
        second-=60;
        ++minute;
    }
    if (minute>59)
    {
        minute%=60,
                hour+=minute/60;
    }
    if (hour>23) hour-=24;
    return temp;
}
CTime CTime::operator++()
{
    if (++second>=60)
    {
        second-=60;
        ++minute;
    }
    if (minute>59)
    {
        minute%=60,
                hour+=minute/60;
    }
    if (hour>23) hour-=24;
    return *this;
}
CTime CTime::operator--(int)
{
    CTime temp(*this);
    second--;
    if (second<0)
    {
        second+=60;
        minute--;
    }
    if (minute<0)
    {
        minute+=60;
        hour--;
    }
    if (hour<0)
    {
        hour+=24;
    }
    return temp;
}
CTime CTime::operator--()
{
    if (--second<0)
    {
        second+=60;
        minute--;
    }
    if (minute<0)
    {
        minute+=60;
        hour--;
    }
    if (hour<0)
    {
        hour+=24;
    }
    return *this;
}
int main ()
{
    CTime t1(8,20,25),t2(11,20,50),t;
    cout<<"t1为：";
    cout<<t1;
    cout<<"t2为：";
    cout<<t2;
    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;
    t=t1+t2;
    cout<<"t1+t2=";
    cout<<t;
    t=t1-t2;
    cout<<"t1-t2=";
    cout<<t;
    t=t1+20;
    cout<<"t1+20=";
    cout<<endl;
    cout<<t;
    t=t2-50;
    cout<<"t2-50=";
    cout<<endl;
    cout<<t1;
    t1+=t2;
    cout<<"t1+=t2";
    cout<<endl;
    cout<<t1;
    t1-=t2;
    cout<<"t1-=t2";
    cout<<endl;
    cout<<t1;
    t1+=20;
    cout<<"t1+=20";
    cout<<endl;
    cout<<t1;
    t1-=50;
    cout<<"t1-=50";
    cout<<endl;
    cout<<t1;
    CTime t3;
    cout<<"请输入时间：";
    cin>>t3;
    cout<<"t3:  ";
    cout<<t3;
    ++t3;
    cout<<"++t3:  ";
    cout<<t3;
    t3++;
    cout<<"t3++:  ";
    cout<<t3;
    --t3;
    cout<<"--t3:  ";
    cout<<t3;
    t3--;
    cout<<"t3--:  ";
    cout<<t3;
    return 0;

}

运行结果：

知识点总结：

在原有程序的基础上，定义对时间对象的自增和自减一目运算符以及定义Time类中的<<和>>运算符重载，实现时间的输入输出，改造原程序中对运算结果显示方式，使程序读起来更自然