'Helper' functions in C++

Question

While refactoring some old code I have stripped out a number of public methods that should actually of been statics as they a) don\'t operate on any member data or call any othe

Answer 1

To add to Pieter's excellent response, another advantage of namespaces is that you can forward declare stuff that you put in a namespace somewhere else, especially structs...

//Header a.h
// Lots of big header files, spreading throughout your code
class foo
{
  struct bar {/* ... */);
};

//header b.h
#include a.h // Required, no way around it, pulls in big headers
class b
{
  //...
  DoSomething(foo::bar);
};

And with namespaces...

//Header a.h
// Big header files
namespace foo
{
  struct bar {/* ... */);
}

//header b.h
// Avoid include, instead forward declare 
//  (can put forward declares in a _fwd.h file)
namespace foo
{
  struct bar;
}

class b
{
  //...
  // note that foo:bar must be passed by reference or pointer
  void DoSomething(const foo::bar & o);
};

Forward declares make a big difference to your compile times after small header changes once you end up with a project spanning hundreds of source files.

Edit from paercebal

The answer was too good to let it die because of an enum error (see comments). I replaced enums (which can be forward-declared only in C++0x, not in today C++) by structs.