Essential C++

4.6. Building an Iterator Class

To illustrate how to overload a set of operators for a class, let’s walk through the implementation of an iterator class. We must support the following usage:

Triangular trian( 1, 8 ); 
Triangular::iterator 
            it = trian.begin(), 
            end_it = trian.end(); 

while ( it != end_it ) 
{ 
    cout << *it << ' '; 
    ++it; 
} 

For this to work, of course, the operators !=, *, and ++ must be defined for objects of the iterator class. How do we do this? We define them as operator member functions. An operator function looks like an ordinary function except that rather than provide the function with a name, we specify the keyword operator followed by the operator we wish to overload. For example,

 class Triangular_iterator { public: ...