What are copy constructors in C++?

What are copy constructors in C++?

Copy constructors are special constructors in C++ used to create a new object as a copy of an existing object.

Can you give me an example of a copy constructor?

Sure! Here's a simple example:

class MyClass {
public:
    int value;
    MyClass(int v) : value(v) {} // Regular constructor
    MyClass(const MyClass &obj) { // Copy constructor
        value = obj.value;
    }
};

This creates a new MyClass object by copying the value from another object.

When is the copy constructor called?

The copy constructor is called when:

1. An object is initialized with another object of the same class.
2. An object is passed by value to a function.
3. An object is returned from a function by value.

What happens if I don't define a copy constructor?

If you don't define a copy constructor, the compiler provides a default one that performs a shallow copy of the object.