Question

During deep copy we are writing overloaded copy constructor and assignment operator.
May i know why we have to write the overloaded assignment operator because we doing the same in overloaded copy constructor(except some check and return this).

Who is calling assignment operator

Answer 1

Follow the Rule of Three:
If you need to write an copy constructor for your class, You also should write the Copy assignment operator and Destructor.

Copy Assignment operator and Copy Constructor both are called Copying functions. They basically help in getting a new copy of an object from an existing object. They both are separate entities invoked in different scenarios. So, just as in case of Copy constructor you ensure that you make deep copies of all pointer members and not just shallow copies, same would applies for copy assignment operator.

An Code Example:

class MyClass obj1, obj2;
class MyClass obj3(obj1);     //Calls Copy Constructor
obj1 = obj2;                  //Calls Copy Assignment Operator