copy constructor

What is a copy constructor?
A copy constructor is a member function which initializes an object using another object of the same class. A copy constructor has the following general function prototype:

 ClassName (const ClassName &old_obj); 

Following is a simple example of copy constructor.

#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