运算符+重载

//demo.h#include <string>class demo{public:    demo();    demo( int a, double b, std::string c );    ~demo();public:    int a;    double b;    std::string c;public:    demo operator+(demo &d2); //二元运算符用成员重载,只需要一个参数,另一个参数由this指针传入};

//demo.cpp#include "demo.h"demo::demo(){    a = 0;    b = 0.0;    c = " ";}demo::demo( int a, double b, std::string c ){    this->a = a;    this->b = b; //this->a = b    this->c = c;}demo::~demo(){}demo demo::operator+( demo &d2) //第一个参数由this指针自动传入到函数中去的.{    demo c;    c.a = this->a + d2.a;    c.b = this->b + d2.b;    c.c = this->c + d2.c;    return c;}

demo a1( 2, 12.5, "Facial " );demo a2( 3, 3.5, "Tissue" );demo c = a1 + a2;