Question

I have recently read Mike McShaffry’s Game Coding Complete and noticed the code style I haven’t seen elsewhere yet. The more important things I noticed were the names of base classes defining interfaces starting with an I like IActor, protected member variables’ names starting with m_ like m_Type and names of virtual methods like VSetId(). To show a bigger, more readable example:

class BaseActor : public IActor 
{ 
    friend class BaseGameLogic;
protected: ActorId m_id; 
    Mat4×4 m_Mat; 
    int m_Type; 
    shared_ptr <ActorParams> m_Params; 
    virtual void VSetID(ActorId id) { m_id = id; } 
    virtual void VSetMat(const Mat4×4 &newMat) { m_Mat = newMat; } 
public: 
    BaseActor(Mat4×4 mat, int type, shared_ptr<ActorParams> params) 
        { m_Mat=mat; m_Type=type; m_Params=params; } 
    /* more code here */
};

I pretty much like this style: it seems justified and looks like it helps increase the overall readability of the code. The question is: Is it a more-or-less established standard? Is there any more to it than the things I mentioned?

Answer 1

That’s called Hungarian Notation. It’s encoding information about the variable into the variable name.

For example, m_params means “a member variable called params”. IActor means “A class called Actor intended to be used as an ifterface”. It is something that is a very hot topic. Most people agree Hungarian Notation is a poor choice, but many will defend what they do as not Hungarian.