Operator Overloading C++

Question

I found this code on internet :

Class Book{
Public:
void operator()(int Counter) const throw();
}

My question is, what operator overloading the above code used?

Answer 1

The above class is basically called a "Functor". It has an overloaded "()" operator. Widely used in STL Algorithms.

Answer 2

Firstly, that code is wrong; since C++ is case sensitive, Class and Public are not keywords. It is also very unusual (albeit legal) to capitalize the first letter of a parameter name (Counter).

Assuming correct capitalization, what you have is an overload of the function-call operator. It allows you to "call" an instance of Book as if it was a function:

Book b;
...
b(23);