What does a compiler add to an empty class declara

2019-02-15 04:20发布

Suppose, I write

class A { };

The compiler should provide (as and when needed)

  1. a constructor
  2. a destructor
  3. a copy constructor
  4. = operator

Is this all the compiler provides? Are there any additions or deletions to this list?

4条回答
Luminary・发光体
2楼-- · 2019-02-15 04:56

The list is not completed............ In addition with the above mention FOUR properties , there is an address operator ( & ) overloaded method , that return the address of the invoking object , is also provided automatically by the compiler.

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不美不萌又怎样
3楼-- · 2019-02-15 04:56

There are five properties:

constructor

copy constructor

destructor

assignment operator

the reference operator(&) - the address

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叛逆
4楼-- · 2019-02-15 05:05

It's complete. But there are two points you should note:

  1. It's the copy =operator. Just like there is a copy constructor, there is a copy assignment operator.
  2. They are only provided if actually used.

Some explanation for 2:

struct A { private: A(); };
struct B : A { };

That's fine! Providing a default constructor would be ill-formed for "B", because it would not be able to call the base-class' constructor. But the default constructor (and the other special functions) is only provided (we say it's implicitly defined) if it's actually needed.

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我想做一个坏孩纸
5楼-- · 2019-02-15 05:07

Your list is complete. This is all it is adding.

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