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
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References: <360D5D93 DOT 499C3AED AT cdworld DOT co DOT uk>
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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

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