What are copy and move constructors in C++?

What are copy and move constructors in C++?

Copy constructors create a new object as a copy of an existing object, while move constructors transfer resources from one object to another.

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) {}
    MyClass(const MyClass &obj) : value(obj.value) {} // Copy constructor
};

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

What about move constructors?

A move constructor transfers resources from a temporary object to a new object. Here's an example:

class MyClass {
public:
    int* value;
    MyClass(int v) : value(new int(v)) {}
    MyClass(MyClass &&obj) : value(obj.value) {
        obj.value = nullptr; // Leave the moved-from object in a valid state
    }
};

This allows efficient resource management.

When should I use move constructors?

Use move constructors when you want to optimize performance by transferring resources instead of copying them, especially with large objects.