What is Copy Constructor

What is a COPY CONSTRUCTOR and when is it called?
A copy constructor is a method that accepts an object of the same class and
copies it’s data members to the object on the left part of assignement.

#include <iostream>
using namespace std;

class Point2D
{
    int x; int y;

    public: int color;
    protected: bool pinned;
    public: Point2D() : x(0) , y(0) {} //default (no argument) constructor
    public: Point2D( const Point2D & ) ;
};

Point2D::Point2D( const Point2D & p )
{
    this->x = p.x;
    this->y = p.y;
    this->color = p.color;
    this->pinned = p.pinned;
}

int main()
{
    Point2D MyPoint;
    MyPoint.color = 345;
    Point2D AnotherPoint = Point2D( MyPoint ); // now AnotherPoint has color = 345
   
    cout << "\n" << AnotherPoint.color << endl;
}

OUTPUT: