Null class in C + +, which class member functions are generated by default.

1. Default member functions

Class Empty

{

Public

Empty (); Default constructor

Empty (const empty&); Copy constructor

~empty (); Destructors

empty& operator= (const empty&); Assignment operators

empty* operator& (); Accessor operator

Const empty* operator& () const; Accessor operator const

};

2. A class can have multiple copy constructors in the following form:

a). For a class X, if the first parameter of a constructor is one of the following:

A) x&

b) Const x&

c) Volatile x&

d) Const volatile x&

And no other parameters or other parameters have default values, then this function is a copy constructor.

X::X (const x&); is a copy constructor

X::x (x&, int = 1); is a copy constructor

X::x (x&, int = 1, float =2.f); is a copy constructor

Null class in C + +, which class member functions are generated by default.