33copyconstr.cpp

#include <iostream>
using namespace std;

class number
{
    int a;

public:
    number() {a = 0;} //default constructor
    number(int x) //parameterized constructor
    {
        a = x;
    }
    number(number &ob) //copy constructor
    {
        a = ob.a; //this takes an class object address as a parameter
        cout << "Using copy constructor function!!" << endl; //to indicate that copy constructor is used
    }
    void show()
    {
        cout << "The number is " << a << endl;
    }
};
int main()
{
    //without using a copy constructor, the compiler will provide a self made constructor to copy the data 
    //so the program will operate without any hinderance
    number p, q, r(6);
    p.show();
    q.show();
    r.show();

    number s(r), t; //here s is declared with r as a parameter passed, so copy constructor will be fetched due to overloading
    s.show();
    t = r; //here no copy constructor is fetched as r is assigned to t manually
    t.show();
    number u = r; //only upon declaration, constructor is fetched
    u.show();
    return 0;
}