From:	"James E Fisher" <James DOT Fisher AT team17 DOT com>
Newsgroups:	comp.lang.c++,comp.os.msdos.djgpp,rec.games.programmer
Subject:	Re: pointer to function ??
Date:	24 Feb 1998 09:36:51 GMT
Organization:	Team 17 Software Ltd
Message-ID:	<01bd4107$bba0dc60$77111111@jfisher.team17.com>
References:	<6c7ltq$ms1$1 AT o DOT online DOT no> <6c7u5l$mub$2 AT news DOT ox DOT ac DOT uk>
NNTP-Posting-Host:	gate-isdn.team17.com
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Thomas Womack <mert0236 AT sable DOT ox DOT ac DOT uk> wrote in article
<6c7u5l$mub$2 AT news DOT ox DOT ac DOT uk>...
> [iC] (jan AT narvik DOT crosswinds DOT net) wrote:

[snip]

> Wouldn't it be easier, and not discernably slower, to put
> 
> int nextthink;
> 
> nextthink=THINKER_RUN;
> nextthink=THINKER_ATTACK;
> 
> switch nextthink
> {
>   case THINKER_RUN:
>     run();
> 
>   case THINKER_ATTACK:
>     attack();
> }
> 
> Tom

The first idea of a pointer to the code is the fastest way as there is only
one call to the required function (after the address of the function has
been fetched).  Using a SWITCH statement is slower as it can end up as a
list of IF() statements by the compiler.

You also need to think about debugging.  Using the pointer to a function is
much cleaner to debug than having to wade through switch statements.
--
James E Fisher, C++ Tools Programmer, Team 17 Software Ltd
http://www.team17.com http://www.geocities.com/SiliconValley/Lakes/5639

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