Copy Constructor in C++

What is Copy Constructor? Write a sample program.

Note: 

The copy constructor is a constructor which creates an object by initializing it with an object of the same class, which has been created previously.

When is copy constructor called?
In C++, a Copy Constructor may be called in following cases:
1. When an object of the class is returned by value.
2. When an object of the class is passed (to a function) by value as an argument.
3. When an object is constructed based on another object of the same class.
4. When compiler generates a temporary object.

Example:

#include<iostream>

using namespace std;

class Point

{

private:

    int x, y;

public:

    Point(int x1, int y1) { x = x1; y = y1; }

    // Copy constructor

    Point(const Point &p2) {x = p2.x; y = p2.y; }

    int getX()            {  return x; }

    int getY()            {  return y; }

};

int main()

{

    Point p1(10, 15); // Normal constructor is called here

    Point p2 = p1; // Copy constructor is called here

    // Let us access values assigned by constructors

    cout << "p1.x = " << p1.getX() << ", p1.y = " << p1.getY();

    cout << "\np2.x = " << p2.getX() << ", p2.y = " << p2.getY();

    return 0;

}

Output:

p1.x = 10, p1.y = 15
p2.x = 10, p2.y = 15