操作符重载

/** Copyright (c) leo* All rights reserved.* filename: f0805.cpp* summary : 重载操作符* version : 1.0* author : leo* date : 6.16.2011*/#include<iostream>#include<iomanip>using namespace std;class Point{int x,y;public:void set(int a, int b);void print()const;friend Point operator+(const Point &a, const Point &b); //普通函数Point operator+(const Point &d); //成员函数friend Point add(const Point &a, const Point &b);friend ostream& operator<<(ostream &o, const Point &d); //不能作成员函数，为访问似有成员加friend};inline void Point::set(int a, int b){x = a;y = b;}inline void Point::print()const{cout<<"("<<x<<", "<<y<<")"<<endl;}ostream& operator<<(ostream &o, const Point &d){return o<<"("<<d.x<<", "<<d.y<<")"<<endl;}Point operator+(const Point &a, const Point &b)//如果是成员函数，则参数个数过多{Point s;s.set(a.x+b.x, a.y+b.y);return s; //返回值，而不能返回引用，因为s是临时量，生命随表达式的结束而结束}inline Point Point::operator+(const Point &d) //成员函数，作为二目操作符其参数个数只能为1{Point s;s.set(x+d.x, y+d.y);return s;}Point add(const Point &a, const Point &b) //普通函数，也可以设计为成员函数{Point s;s.set(a.x+b.x, a.y+b.y);return s;} int main(){Point a,b,c ;a.set(3,2);b.set(1,5);(a+b).print();a.operator +(b).print();add(a,b).print();cout<<(a+b)<<endl;return 0;}

 

/** Copyright (c) leo* All rights reserved.* filename: f0806.cpp* summary : Time类的operator++重载* version : 1.0* author : leo* date : 6.17.2011*/#include<iostream>#include<iomanip>using namespace std;class Time{int hour, minute, second;public:void set(int h, int m, int s);friend Time& operator++(Time &a); //前自增friend Time operator++(Time &a, int);//后自增friend ostream& operator<<(ostream &o, const Time &t);};inline void Time::set(int h, int m, int s){hour = h;minute = m;second = s;}Time & operator++(Time &a) //前增量，返回对象的引用{if(!(a.second = (a.second+1)%60) && !(a.minute = (a.minute+1)%60))a.hour = (a.hour+1)%24;return a;}Time operator++(Time &a, int) //后增量，返回临时对象{Time t(a); //t 与 a不是同一个实体，t是对a的拷贝if(!(a.second = (a.second+1)%60) && !(a.minute = (a.minute+1)%60))a.hour = (a.hour+1)%24;//原参数对象发生了变化return t; //返回一个临时对象，是参数对象变化以前的值}ostream & operator<<(ostream &o, const Time &t)//重载输出流{o<<setfill('0')<<setw(2)<<t.hour<<":"<<setw(2)<<t.minute<<":"<<setw(2)<<t.second<<"/n"<<setfill(' ');return o;}int main(){Time t;t.set(11, 59, 58);cout<<t++; //11:59:58cout<<endl<<++t; //12:00:00return 0;}