自动调用类的构造函数生成临时类对象

#include <iostream>

#include <vector>

using namespace std;

class point;

point operator + (point p1,point p2);

ostream & operator << (ostream &out,point &p);

class point

{

public:

point(int a,int b=10)

{

x=a;

y=b;

}

friend point operator + (point p1,point p2);

friend ostream & operator << (ostream &out,point &p);

private:

int x;

int y;

};

point operator + (point p1,point p2)

{

return point(p1.x+p2.x,p1.y+p2.y);

}

ostream & operator << (ostream &out,point &p)

{

cout<<p.x<<'\0'<<p.y;

return out;

}

int main()

{

point p1(2,3),p2(4,5);

point p=p1+p2;

p=p1+2; //这里会做自动类型转换，调用类型转换函数或者构造函数 给跪了

cout<<p<<endl;

return 0;

}