Suppose, I write
class A { }; The compiler should provide (as and when needed)
- a constructor
- a destructor
- a copy constructor
- = operator
Is this all the compiler provides? Are there any additions or deletions to this list?
- 3I came across this old question just now... for the benefit of future visitors it's probably worth mentioning that in C++11 a move constructor as well as a move assignment operator are auto-generated in addition to the above.jogojapan– jogojapan2013-02-25 13:30:56 +00:00Commented Feb 25, 2013 at 13:30
Add a comment |
5 Answers
It's complete. But there are two points you should note:
- It's the copy =operator. Just like there is a copy constructor, there is a copy assignment operator.
- 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.
answered Apr 17, 2010 at 20:40
Johannes Schaub - litb
510k132 gold badges928 silver badges1.2k bronze badges
1 Comment
Steve Jessop
I guess you could argue that in the case of an empty class, the compiler also adds at least one byte of padding ;-)
From C++11 onwards, in addition to what you have listed
- Move ctor
- Move assignment operator
Comments
Your list is complete. This is all it is adding.
Comments
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.
Comments
There are five properties:
constructor
copy constructor
destructor
assignment operator
the reference operator(&) - the address
