第八周实验报告（二）

实现累中运算符的重载

 

#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:41:15CTime operator-(CTime &c);//对照+理解CTime operator+(int s);//返回s秒后的时间CTime operator-(int w);//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 w);//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int 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<<"t1与t2的和为";t = t1 + t2;t.display();cout<<"差"<<endl;t = t1 - t2;t.display();cout<<"在t1的基础上加2s"; t = t1 + 2;t.display();cout<<"在t1的基础上减2s"; t = t1 - 2;t.display();cout<<"t1前置加1s";    ++t1;    t1.display();        cout<<"t1后置加1s";    t1++;    t1.display();        cout<<"t1前置减1s";    --t1;    t1.display();        cout<<"t1后置减1s";    t1--;    t1.display();        cout<<"t1+=t2    ";    t1+=t2;    t1.display();        cout<<"t1-=t2    ";    t1-=t2;    t1.display();        cout<<"t1+=2     ";    t1+=2;    t1.display();        cout<<"t1-=2     ";    t1-=2;    t1.display();     cout<<endl;system("pause");return 0;//下面自行设计对其他运算符的重载的测试}void CTime::setTime(int h,int m,int s){hour = h;minute = m;second = s;}void CTime::display(){cout<<hour<<":"<<minute<<":"<<second<<endl;}bool CTime::operator>(CTime &t){if(hour>t.hour){return true;}elsereturn false;}bool CTime::operator<(CTime &t){if(hour<t.hour){return true;}elsereturn false;}bool CTime::operator ==(CTime &t){if(hour==t.hour&&minute==t.minute&&second==t.second)return true;elsereturn false;}bool CTime::operator >=(CTime &t){    if(hour==t.hour&&minute==t.minute&&second==t.second)return true;elsereturn false;}bool CTime::operator <=(CTime &t){if(hour==t.hour&&minute==t.minute&&second==t.second)return true;else return false;}bool CTime::operator !=(CTime &t){if(hour!=t.hour||minute!=t.minute||second!=t.second)return true;elsereturn false;}CTime CTime::operator+(CTime &c){CTime a;a.hour = hour + c.hour;if(a.hour>24)a.hour -= 24;a.minute = minute + c.minute;if(a.minute>=60){a.minute -= 60;a.hour+=1;}a.second = second + c.second;if(a.second>=60){a.second -= 60;a.minute+=1;if(a.minute>=60){a.minute -= 60;a.hour+=1;}}return a;}CTime CTime::operator -(CTime &c){      int h,m,s;            h = hour - c.hour;      m = minute - c.minute;      s = second - c.second;      if(s<0)      {             s=(-s);             m--;      }       if(m<0)      {             m=60+m;             h--;      }      while (h<0) h=-h;      CTime a(h,m,s);                     return a;             }CTime CTime::operator+(int s){      CTime a;    a.second = second + s;if(a.second>=60){a.second -= 60;a.minute=minute+1;    }    else    a.minute = minute;if(a.minute>=60){a.minute -= 60;a.hour=hour+1;}elsea.hour = hour;return a;}CTime CTime::operator-(int w){      int h,m,s;      h = hour ;      m = minute ;      s = second - w;      if(s<0)      {             s=(-s);             m--;      }      if(m<0)      {             m=60+m;             h--;      }      if(h<0)      {             h=(-h);      }      CTime a(h,m,s);      return a;}CTime CTime::operator++(int)//后置++，下一秒   从这里开始以后使用重载过的运算符，使程序更为简单{      CTime t=*this;          //*this指的是指向CTime类的成员对象，因为定义的重载的运算符需要一个是类才自动使用    *this=*this+1;          //这里定义了t=*this是因为需要后置一下秒，所以返回的是原来的类的对象成员，并且在原来的基础上*this+1s    return t;  }    CTime CTime::operator++()//前置++，下一秒  {      *this=*this+1;         //这里没有定义CTime t是因为前置返回的是变化后的类的对象成员    return *this;  }    CTime CTime::operator--(int)//后置--，前一秒   //与++雷同{      CTime t=*this;      *this=*this-1;      return t;  }    CTime CTime::operator--()//前置--，前一秒  {      *this=*this-1;      return *this;  }  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;  } 

 

 

①：unsigned表示无符号数，就是部分正负，所以在重载“ - ”的时候需要定义int型的变量做中间传递。

②：学会使用重载的运算符在其他函数中的运用。

③：注意CTime CTime::operator -(CTime &c)
{
      int h,m,s;
     
      h = hour - c.hour;
      m = minute - c.minute;
      s = second - c.second;
      if(s<0)
      {
             s=(-s);
             m--;
      }
      if(m<0)
      {
             m=60+m;
             h--;
      }
      while (h<0) h=-h;
      CTime a(h,m,s);               
      return a;
            
}                             注意定义返回的CTime a必须在最后，如果在该函数最前定义的话会出现错误。