Special member functions

In the C++ programming language, special member functions are functions which the compiler will automatically generate if they are used, but not declared explicitly by the programmer.
The automatically generated special member functions are:

Default constructor if no other constructor is explicitly declared.
Copy constructor if no move constructor and move assignment operator are explicitly declared.
Move constructor if no copy constructor, copy assignment operator, move assignment operator and destructor are explicitly declared.
Copy assignment operator if no move constructor and move assignment operator are explicitly declared.
Move assignment operator if no copy constructor, copy assignment operator, move constructor and destructor are explicitly declared.
Destructor

In these cases the compiler generated versions of these functions perform a memberwise operation. For example, the compiler generated destructor will destroy each sub-object of the object.
The compiler generated functions will be public, non-virtual and the copy constructor and assignment operators will receive const& parameters.

Example

The following example depicts two classes: for which all special member functions are explicitly declared and for which none are declared.

include
include
include

class Explicit ;
class Implicit : public Explicit ;

Signatures

Here are the signatures of the special member functions:

Function	syntax for class MyClass
Default constructor	`MyClass;`
Copy constructor	`MyClass;`
Move constructor	`MyClass noexcept;`
Copy assignment operator	`MyClass& operator=;`
Move assignment operator	`MyClass& operator= noexcept;`
Destructor	`virtual ~MyClass;`

C++03

In C++03 before the introduction of move semantics the special member functions were:

Default constructor
Copy constructor
Copy assignment operator
Destructor