struct中构造函数写法，重载运算符写法

#include<iostream>
using namespace std;
struct Point{
	int x,y;
	Point(int x=0,int y =0):x(x),y(y) {}
}; 
ostream& operator << (ostream &out, const Point A){
	out << A.x << ' ' << A.y<<endl;
	return out;
}
Point operator + (const Point& A, const Point& B){
	return Point(A.x+B.x,A.y+B.y);
}
int main()
{
	Point a, b(1,2);
	a.x = 3;
	cout << a+b << "\n";
	return 0;
}