From:	sparhawk AT eunet DOT at (Gerhard Gruber)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: fast way to do a if statement
Date:	Sat, 26 Sep 1998 22:18:05 GMT
Organization:	Customer of EUnet Austria
Lines:	51
Message-ID:	<3610650f.47252487@news.Austria.EU.net>
References:	<360D5D93 DOT 499C3AED AT cdworld DOT co DOT uk>
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NNTP-Posting-Date:	26 Sep 1998 22:20:21 GMT
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Destination: Craig Rothwell <craig AT cdworld DOT co DOT uk>
From: Gruber Gerhard
Group: comp.os.msdos.djgpp
Date: Sat, 26 Sep 1998 22:33:08 +0100:

>I have a little program I have
>writen to decode something but
>most of the program is taken up
>with:
>
>if (x==1) do...
>if (x==2) do...
>if (x==3) do...
>if (x==4) do...
>if (x==5) do...

switch(x)
{
	case 1:
    do something
   break;

   case 2:
    do something
   break;
   
	default:
	  do something else
   break;
}


>That goes on for about 40 lines.
>Is there a way to do it quicker
>that would mean less messing
>about for the CPU?

This is faster because usually the compiler generates a jumptable for this. Of
course if the numbers start from 0 or they are subsequently you can use a jump
table.
--
Bye,
   Gerhard

email: sparhawk AT eunet DOT at
       g DOT gruber AT sis DOT co DOT at

Spelling corrections are appreciated.
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