关于时间的计算

输入：T1= 11时:50分:40秒，T2= 12时:20分:20秒

输出：T2-T1= 0时:29分:40秒

---

#include <iostream>
#include <stdio.h>
using namespace std;
class Data
{
private:
    int hour;
    int minute;
    int second;

public:
    Data(int phour =0,int pminute =0,int psecond =0):hour(phour),minute(pminute),second(psecond) {}
    friend Data operator-(const Data&T1,const Data&T2);
    friend ostream&operator<<(ostream&out,const Data&T);
    void showtime()const;
};
void Data::showtime()const
{
    cout<<hour<<":"<<minute<<":"<<second<<endl;
};
Data operator-(const Data&T1,const Data&T2)
{
    int ih, im, is;
    ih = T1.hour-T2.hour;
    im = T1.minute-T2.minute;
    is = T1.second-T2.second;
    if(is < 0)
    {
        is = 60 +is;
        im--;
    }
    if(im < 0)
    {
        im = 60 +im;
        ih--;
    }
    return Data(ih,im,is);
}
ostream & operator<<(ostream&out,const Data&T)
{
    out<<T.hour<<"时"<<":"<<T.minute<<"分"<<":"<<T.second<<"秒"<<endl;
    return out;
}
int main()
{
    Data T1(11,50,40),T2(12,20,20);
    Data T3;
    //T3.showtime();
    cout<<"T1= "<<T1<<endl;
    cout<<"T2= "<<T2<<endl;
    T3=T2-T1;
    cout<<"T2-T1= "<<T3<<endl;
    return 0;
}

方法一：

Data operator-(const Data&T1,const Data&T2)
{
    int ih, im, is, sum_sec;
    sum_sec=(T1.hour*3600+T1.minute*60+T1.second) - (T2.hour*3600+T2.minute*60+T2.second);
    ih = sum_sec/3600;
    im = sum_sec%3600/60;
    is = sum_sec%60;
    return Data(ih,im,is);
}

方法二：

Data operator-(const Data&T1,const Data&T2)
{
    int ih, im, is;
    ih = T1.hour-T2.hour;
    im = T1.minute-T2.minute;
    is = T1.second-T2.second;
if(is < 0)
    {
        is = 60 +is;
        im--;
    }
    if(im < 0)
    {
        im = 60 +im;
        ih--;
    }
    return Data(ih,im,is);
}