Constructor which is used to create or initialized new object from pre existing object called copy constructor .
This constructor takes one argument. Also called one argument constructor. The main use of copy constructor is to initialize the objects while in creation, also used to copy an object. The copy constructor allows the programmer to create a new object from an existing one by initialization.

#include<iostream.h>
#include<conio.h>
class A{
	int x;
	int y;
	public:
		A(int i, int j){
			x=i;
			y=j;
		}
		A(A &ob){
			x=ob.x;
			y=ob.y;
		}
		void displaly(){
			cout<<x<<" "<<y<<endl ;
		}
};

void main(){
	A obj(5,6);
	A obj1(obj);
	obj.display();
	obj1.display();
}