对重载输出符不了解

C/C++ code

#include <iostream.h>class point {    int x;    int y;    public:    point(int xx=0,int yy=0):x(xx),y(yy){};    void setvalue();    friend ostream& operator<< (ostream& os,const piont& obj);};void point::setvalue (){    cout<<"please enter the value!"<<endl;    cin>>x>>y;}ostream& operator<< (ostream& os,const point& obj){        os<<obj.x<<" "<<obj.y;        return os;}void main(){    point p1；         p1.setvalue ();        cout<<p1;}

C/C++ code

#include <iostream> using namespace std;class point {     int x;     int y; public:     point(int xx=0,int yy=0):x(xx),y(yy){};     void setvalue();     friend ostream& operator<< (ostream& os, const point& obj); //point, not piont!!!};     void point::setvalue (){     cout<<"please enter the value!"<<endl;     cin>>x>>y; } ostream& operator<< (ostream& os,const point& obj){     os<<obj.x<<" "<<obj.y;     return os; } int main(){     point p1;    p1.setvalue ();     cout<<p1;     return 0;}