第十二周阅读程序1

////  main.cpp//  project////  Created by 徐伟 on 6/15/16.//  Copyright © 2016 fizz_i. All rights reserved.//#include <iostream>using namespace std;class Sample{private:    int x;public:    Sample () { }    Sample(int a){x=a;}    void disp(){cout<<"x="<<x<<endl;}    friend Sample operator+( Sample &s1, Sample &s2);};Sample operator+( Sample &s1, Sample &s2){    return Sample(s1.x+s2.x);}int main(){    Sample obj1(10);    Sample obj2(20);    Sample obj3;    obj3=obj1+obj2;    obj3.disp();    return 0;}