What is the difference between a copy constructor and an overloaded assignment operator?

Answer:

A copy constructor constructs a new object by using the content of the argument object. An overloaded assignment operator assigns the contents of an existing object to another existing object of the same class.

#include<iostream>
using namespace std;
class Demo
{
public:
    Demo() {}
    Demo(const Demo &obj)
    {
        cout<<"Copy constructor called "<<endl;
    }
    Demo& operator = (const Demo &obj)
    {
        cout<<"Assignment operator called "<<endl;
        return *this;
    }
};
int main()
{
    Demo a, b;
    //calls assignment operator
    b = a;
    // calls copy constructor
    Demo c = a;
    return 0;
}

Output:

Assignment operator called.
Copy constructor called.