What are the advans/disadvans of using class member functions vs normal functions?
Author
I just learned how to use classes and their member functions, and I was just wondering if they are slower or faster then normal functions and if they have other advantages, and what about class arrays? for example:
class TIME{
public:
.....
private:
.....
} time[5];
are the member functions in there gonna be just as fast as if I were to use a struct and just write my own normal functions?
Possibility
There might be a slight performance difference due to implementation details, but there is no reason why a member function should be any faster/slower than a normal function.
Certainly if there is a difference, it will not be very significant, at most the cost of pushing a few more things onto the stack in the function call.
#pragma DWIM // Do What I Mean!
~ Mad Keith ~
**I use Software Mode**
Certainly if there is a difference, it will not be very significant, at most the cost of pushing a few more things onto the stack in the function call.
#pragma DWIM // Do What I Mean!
~ Mad Keith ~
**I use Software Mode**
As long as you don''t use virtual member methods and/or virtual inheritance, member methods are as fast as normal C functions.
The only difference is that member methods internally have one (implicit) parameter: the this pointer. The value of the this pointer is pushed to the stack prior to calling the member function.
int A::b() { /* ... */; return 0; }
is roughly implemented as
int A__b(const A *this) { /* ... */; return 0; }
However, if you''d try to achieve encapsulation in C, you''d probably end up doing it the same way.
Erik
The only difference is that member methods internally have one (implicit) parameter: the this pointer. The value of the this pointer is pushed to the stack prior to calling the member function.
int A::b() { /* ... */; return 0; }
is roughly implemented as
int A__b(const A *this) { /* ... */; return 0; }
However, if you''d try to achieve encapsulation in C, you''d probably end up doing it the same way.
Erik
Don''t let this performance hit discourage you.. Lots of games use OO techniques (Half-Life, etc.) and I, for one, think this is one of the waves of the future in game design.
Just my opinion, though I know others share it.
------------------------------
Jonathan Little
invader@hushmail.com
http://www.crosswinds.net/~uselessknowledge
Just my opinion, though I know others share it.
------------------------------
Jonathan Little
invader@hushmail.com
http://www.crosswinds.net/~uselessknowledge
I agree - OO is the way to go. Many good things have caused slight performance hits but resulted in massive productivity improvements and algorithmic improvements.
#pragma DWIM // Do What I Mean!
~ Mad Keith ~
**I use Software Mode**
#pragma DWIM // Do What I Mean!
~ Mad Keith ~
**I use Software Mode**
Author
So what does Object oriented programming actually mean. I am fairly certain I already do that, but what is it precisely and why is SO good?
Possibility
Possibility
I have programmed in C++ for about 4 months now, and have pondered the exact same thing... anyone?
GO LEAFS GO!
GO LEAFS GO!
I have been programming in C++ for a few months now, and, although I have learnt and can understand Classes and OOP, I have never actually used them in a project, as I''ve never really seen the need. I never did understand what the advantages/disadvantages were.
This topic is closed to new replies.
Advertisement
Popular Topics
Advertisement