I am trying to make a point class for school, and I get this error: "Error E2080 Point.h 20: 'Point::operator <<(ostream &,const Point &)' must be declared with one parameter". I have no idea what to do, as I had code that worked before like this with the apmatrix class. This is my code (all the relevant parts):

Code:
//Point.h
#include <iostream>
using namespace std;

class Point
{
public:
    ostream& operator <<(ostream&, const Point&);
private:
    int m_x;
    int m_y;
};

//Point.cpp
ostream& Point::operator <<(ostream& os, const Point& p)
{
    os << "(" << p.m_x << "," << p.m_y << ")";
    return *this; //?
}