第四章 重载课堂作业

#include<iostream>    #include<string>    using namespace std;    class Time    {    public:        void display()    {        cout<<hour<<":"<<minute<<":"<<sec<<endl;    }    protected:        int hour;        int minute;        int sec;    };    class Date    {    public:        void display1()    {        cout<<year<<":"<<month<<":"<<day<<endl;    }    protected:        int year;        int month;        int day;    };    class DateTime:public Time,public Date    {     public:        friend istream& operator >>(istream &input,DateTime &t1);    /*运算符的>> << + -的重载都设为友元函数  */      friend ostream& operator <<(ostream &output,DateTime &t1);        friend DateTime operator +(DateTime &t1,DateTime &t2);        friend DateTime operator -(DateTime &t1,DateTime &t2);    private:       string place;    };    istream& operator >>(istream &input,DateTime &t1)    {        input>>t1.place>>t1.year>>t1.month>>t1.day>>t1.hour>>t1.minute>>t1.sec;        return input;    }    ostream& operator<<(ostream &output,DateTime &t1)    {        output<<t1.place<<":"<<t1.year<<"/"<<t1.month<<"/"<<t1.day<<"/"<<t1.hour<<":"<<t1.minute<<":"<<t1.sec;        return output;    }    DateTime operator +(DateTime &t1,DateTime &t2)    {        DateTime t3;        t3.sec=t1.sec+t2.sec;        t3.minute=t1.minute+t2.minute;        t3.hour=t1.hour+t2.hour;        t3.day=t1.day+t2.day;        t3.month=t1.month+t2.month;         t3.year=t1.year;        t3.place=t1.place;         if(t3.sec>60)        {            t3.sec-=60;            t3.minute+=1;        }        if(t3.minute>60)        {            t3.minute-=60;            t3.hour+=1;        }        if(t3.hour>24)        {            t3.hour-=24;            t3.day+=1;        }        if(t3.month==1||3||5||7||8||10||12)        {            if(t3.day>31)            {                t3.day-=31;                t3.month+=1;            }        }        if(t3.month==4||6||8||10||11)        {            if(t3.day>30)            {                t3.day-=30;                t3.month+=1;            }        }        if(t3.month==2)        {            if(t3.day>28)            {                t3.day-=28;                t3.month+=1;            }        }        if(t3.month>12)        {            t3.month-=12;            t3.year+=1;        }        return t3;      }    DateTime operator -(DateTime &t1,DateTime &t2)    {        DateTime t3;        t3.sec=t1.sec-t2.sec;        t3.minute=t1.minute-t2.minute;        t3.hour=t1.hour-t2.hour;        t3.day=t1.day-t2.day;        t3.month=t1.month-t2.month;         t3.year=t1.year;        t3.place=t1.place;         if(t3.sec<0)        {            t3.sec+=60;            t3.minute-=1;        }        if(t3.minute<0)        {            t3.minute+=60;            t3.hour-=1;        }        if(t3.hour<0)        {            t3.hour+=24;            t3.day-=1;        }        if(t3.month==1||3||5||7||8||10||12)        {            if(t3.day<0)            {                t3.day+=31;                t3.month-=1;            }        }        if(t3.month==4||6||8||10||11)        {            if(t3.day<0)            {                t3.day+=30;                t3.month-=1;            }        }        if(t3.month==2)        {            if(t3.day<0)            {                t3.day+=28;                t3.month-=1;            }        }        if(t3.month<0)        {            t3.month+=12;            t3.year-=1;        }        return t3;      }            int main()    {        DateTime d1,d2,d3,d4;        cout<<"地点："<<'\t'<<"年："<<'\t'<<"月"<<'\t'<<"日"<<'\t'<<"时"<<'\t'<<"分"<<'\t'<<"秒"<<endl;         cin>>d1;        cin>>d2;         cout<<"两时间相加为："<<endl;         d3=d1+d2;        d4=d1-d2;        cout<<d3<<endl;        cout<<"两时间相减为："<<endl;        cout<<d4<<endl;    }