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Structs vs Classes??

RedGenie · 2002-10-22T21:21:26

Does anybody have any ideas on the pros and cons of using Classes against Structs partivularly from a performance point of view. Lets say ive got 100 characters and I increment their position within a loop. The Class way: /////////////////////////// //Character Class (CCharacter) /////////////////////////// POINT charPosition; POINT GetPosition() { return charPosition; } void SetPosition(POINT newPosition) { charPosition=newPosition; } /////////////////////////// // Main program /////////////////////////// CCharacter aCharacter[100]; for(int characterCount=0;characterCount<100;characterCount++) { int newxPos=aCharacter[characterCount].GetPosition().x+1; int newyPos=aCharacter[characterCount].GetPosition().y+1; aCharacter[characterCount].SetPosition({newxPos,newyPos}); } And the struct way: /////////////////////////// // Main program /////////////////////////// struct { POINT charPosition; } CHARACTER; CHARACTER aCharacter[100]; for(int characterCount=0;characterCount<100;characterCount++) { int newxPos=aCharacter[characterCount].charPosition.x+1; int newyPos=aCharacter[characterCount].charPosition.y+1; aCharacter[characterCount].charPosition={newxPos,newyPos}; } Would the struct way be significantly faster? Probably not for 100 characters, but lets say 2000. This is simplified code, the character class would obviously contain much more functionality but im just wanting to know if there is any significant overhead in having the code class based. (Or is a struct basically a class anyway in which case I guess there would be no difference).

General and Gameplay Programming Programming

Started by RedGenie October 21, 2002 09:49 PM

33 comments, last by RedGenie 21 years, 6 months ago

Alpha_ProgDes

6,963

October 22, 2002 07:53 AM

you know what!
someone should make a game programming book on when to use certain structures and functions (functions as in inline, inheritance, struct vs class, array vs pointer; not like void dropHealth ()

back to subject (please don''t erase above paragraph), if putting your function in the header file subjects them to being inline why don''t most programmer do that? well for the functions that need to be inline, not every class function they have.

so my question ultimately comes back to the original post (sorta) would code run quicker if you had (C)structs & functions or classes?

Beginner in Game Development? Read here. And read here.

Qw3r7yU10p!

819

October 22, 2002 08:23 AM

c++ struct and class info

i thought i'd mention something else too.

herb sutter commented that inline functions don't always give you the boost you imagine. in fact he says it can sometimes have detrimental effects. he says it's best to leave stuff like inlining until you can show that your application requires it and that it does improve the code.

madkeithv, you've got a tough job. thanks for all the time and effort you put. we all need to just take a few deep breaths.

i won't tell mum.

peace

edit: html

[edited by - petewood on October 22, 2002 9:24:26 AM]

Stoffel

250

October 22, 2002 11:59 AM

Three rules to optimization:
1) Don''t optimize
2) Don''t optimize yet
3) Only optimize what a profiler specifically tells you to optimize

inlining has a huge drawback of tight physical coupling of implementation to clients. If a profiler tells you that a function is a bottleneck, try inlining it; usually, you shouldn''t do so until that point.

Anonymous

October 22, 2002 05:24 PM

structs did not have the abilities of class in C. They were updated, updating them did not disturb any backwords compatibilty so there was no reason not to give structs OO capabilties.

Thrump

169

October 22, 2002 09:21 PM

quote:Original post by Stoffel
Three rules to optimization:
1) Don''t optimize
2) Don''t optimize yet
3) Only optimize what a profiler specifically tells you to optimize

Amen brother! Some of my code is SO slow, but it only gets called once per frame, so only anal programmers get bothered by it (as opposed to the end user). I always err on the side of readability. (that is, until rule 3 comes into play)

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