01Copy_constructor.cpp

/*
What is copy constructor C++?
Image result for copy constructor in c++
Copy constructor is called when a new object is created from an existing object, as a copy of the existing object. Assignment operator is called when an already initialized object is assigned a new value from another existing object.
*/#include <iostream>
using namespace std;
class student
{
    int id;

public:
    student()
    {
    }
    student(int a)
    {
        id = a;
    }
    student(student &s)
    {
        id = s.id;
    }
    int display()
    {
        return id;
    }
};

int main()
{
    system("cls");
    student s1(200);
    student s2(s1);
    student s3(s2);
    student s4(s1);
    cout << "Id of student s1 = " << s1.display()<<endl;
    cout << "Id of student s2 =" << s1.display()<<endl;
    cout << "Id of student s3 =" << s1.display()<<endl;
    cout << "Id of student s4 =" << s1.display()<<endl;
}