What is the difference between assignment operator and copy constructor?

Copy constructor is a constructor — a function whose job it is to turn raw storage into an object of a specific class. An assignment operator, on the other hand, copies state between two existing objects. In other words, an assignment operator has to take into account the current state of the object when copying the other object’s state into it. The copy constructor is creating a new object from raw storage and knows it’s writing over garbage.