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copied!<p>I think what you are looking for is something called the "pimpl idiom". To understand how this works, you need to understand that in C++ you can forward declare something like so.</p> <pre><code>class CWidget; // Widget will exist sometime in the future CWidget* aWidget; // An address (integer) to something that // isn't defined *yet* // later on define CWidget to be something concrete class CWidget { // methods and such }; </code></pre> <p>So to forward declare means to promise to fully declare a type later. Its saying "there will be this thing called a CWidget, I promise. I'll tell you more about it later.".</p> <p>The rules of forward declaration say that you can define a pointer or a reference to something that has been forward declared. This is because pointers and references are really just addresses-a number where this yet-to-be-defined thing will be. Being able to declare a pointer to something without fully declaring it is convenient for a lot of reasons.</p> <p>Its useful here because you can use this to hide some of the internals of a class using the "pimpl" method. Pimpl means "pointer to implementation". So instead of "widget" you have a class that is the actual implementation. The class you are declaring in your header is just a pass-through to the CImpl class. Here's how it works:</p> <pre><code>// Thing.h class CThing { public: // CThings methods and constructors... CThing(); void DoSomething(); int GetSomething(); ~CThing(); private: // CThing store's a pointer to some implementation class to // be defined later class CImpl; // forward declaration to CImpl CImpl* m_pimpl; // pointer to my implementation }; </code></pre> <p>Thing.cpp has CThing's methods defined as pass-throughs to the impl:</p> <pre><code>// Fully define Impl class CThing::CImpl { private: // all variables public: // methods inlined CImpl() { // constructor } void DoSomething() { // actual code that does something } //etc for all methods }; // CThing methods are just pass-throughs CThing::CThing() : m_pimpl(new CThing::CImpl()); { } CThing::~CThing() { delete m_pimpl; } int CThing::GetSomething() { return m_pimpl->GetSomething(); } void CThing::DoSomething() { m_impl->DoSomething(); } </code></pre> <p>tada! You've hidden all the details in your cpp and your header file is a very tidy list of methods. Its a great thing. The only thing you might see different from the template above is that people may use boost::shared_ptr<> or other smart pointer for the impl. Something that deletes itself.</p> <p>Also, keep in mind this method comes with some annoyances. Debugging can be a tad bit annoying (extra level of redirection to step through). Its also a lot of overhead for creating a class. If you do this for every class, you'll get tired of all the typing :). </p>

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