在学习....

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每天忙于逻辑和技术之外，也需要完善基础的知识体系....

今天学习C++的运算符重载...

#ifndef POINT_H#define POINT_H#include <iostream>class Point{public:    Point();    Point(const Point& p);    Point(int nx, int ny);    bool isNull() const;    void setX(int x);    int x() const;    void setY(int y);    int y() const;    Point &operator +=(const Point &p); //只重载+=, -=,乘除未写出    Point &operator -=(const Point &p);    friend inline bool operator==(const Point &, const Point &);    friend inline bool operator!=(const Point &, const Point &);    friend inline const Point operator+(const Point &, const Point &);    friend inline const Point operator-(const Point &, const Point &);    friend inline std::ostream& operator<<(std::ostream &ot, const Point &);private:    int m_x;    int m_y;};

inline bool operator==(const Point &a, const Point &b){    return a.x() == b.x() && a.y() == b.y();}inline bool operator!=(const Point &a, const Point &b){    return a.x() != b.x() || a.y() != b.y();}inline const Point operator+(const Point &a, const Point &b){    Point p;    p.setX(a.x() + b.x());    p.setY(a.y() + b.y());    return p;}inline const Point operator-(const Point &a, const Point &b){    Point p;    p.setX(a.x() - b.x());    p.setY(a.y() - b.y());    return p;}inline std::ostream& operator<<(std::ostream &ot, const Point &p){    ot << "x:" << p.x() << ",y:" << p.y() << std::endl;    return ot;}#endif // POINT_H

自定义了类方便使用

#include "point.h"Point::Point()    :m_x(0),m_y(0){}Point::Point(const Point &p){    this->m_x = p.x();    this->m_y = p.y();}Point::Point(int nx, int ny){    m_x = nx;    m_y = ny;}bool Point::isNull() const{    return m_x == 0 && m_y == 0;}void Point::setX(int x){    m_x = x;}int Point::x() const{    return m_x;}void Point::setY(int y){    m_y = y;}int Point::y() const{    return m_y;}Point &Point::operator +=(const Point &p){    m_x += p.x();    m_y += p.y();    return *this;}Point &Point::operator -=(const Point &p){    m_x -= p.x();    m_y -= p.y();    return *this;}

理解,自定义数据结构类,在作为函数参数,申明为const引用的好处,在于高效,不声明引用的情况下,参数会进行拷贝,效率不高.

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