Const and Reference

[Ramzi89]

Write your question here.

What does the const at the end of this function definition mean?

  virtual double area() const;

[vlad from moscow]

It means that the implicit first parameter this of the member function will have the qualifier const.

[coder777]

i.e. you cannot modify member variables (except using mutable)

[MiiNiPaa]

And it can be invoked on constant objects of said class.

[Ramzi89]

Can you only have this sort of definition with member functions or procedures?

[ypfz3TCk]

The purpose of const is to modify the type of the implicit 'this' pointer. By default *this is a const pointer to a noncont version of the class type.

To answer your second question - this type of definition only arises in the contest of a class member function. *this is a pointer to a member of the object instance.

[Ramzi89]

Brilliant!