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Code Snippets / Switch a boolean variable using formula (no if statement)

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Neil Young
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Posted: 30th Aug 2005 01:58 Edited at: 30th Aug 2005 02:00
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I wanted to switch a boolean variable back and forth between 0 and 1 during a specific function without using hard-coded if statements (to determine it's present value first and then switch its value accordingly). Pure math can't do this alone, but when I went to sit on the can the wrapvalue command occured to me.



This was a tough puzzle at the time but I figured a good solution (maybe there is better if someone can contribute). Hope this makes your code more friendly!
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Lost in Thought
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Posted: 30th Aug 2005 11:06 Edited at: 30th Aug 2005 11:07
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Cool but using if is way faster.



Appx 6.5 times faster here.



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Math89
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Posted: 30th Aug 2005 11:50
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You can use NOT : value = not value.
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Lost in Thought
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Posted: 30th Aug 2005 13:50
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Yes you can use the not operator, but remember it only tests bit 0 so it may be 1 cycle off if the beginning value is other than 1 or 0(like the wrapvalue method) when starting. Thats why I used > 0 as the test to keep it boolean from the beginning. Also the NOT operator is slightly the fastest method, I don't see how I forgot it

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TDK
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Posted: 31st Aug 2005 07:42
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Quote: "Also the NOT operator is slightly the fastest method, I don't see how I forgot it"


And lets not forget that DBC users haven't got the NOT operator...

TDK_Man

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Sven B
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Posted: 31st Aug 2005 12:47
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Improvisation:





Immunity and Annihalation makes Immunihalation...
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Jukuma
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Posted: 31st Aug 2005 18:18
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this works for all i think

value = abs(value - 1)
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Jukuma
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Posted: 1st Sep 2005 02:25
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do
print abs(null - 1)
wait 1000
loop

bye
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empty
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Posted: 1st Sep 2005 03:06
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or even shorter

value = 1 - value


Play Nice! Play Basic! Version 1.088
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Xolatron old
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Posted: 1st Sep 2005 03:08
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Or use this great code without if's; I really think it's probably fastest (basically it's a better NOT that will work in DBC)


-Xol


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BatVink
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Posted: 1st Sep 2005 16:44
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Nice one, empty, you win!

Xolatron, your value will always be 0!

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Phaelax
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Posted: 1st Sep 2005 16:57
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I always like to make constants in my program:

#constant TRUE = 1
#constant FALSE = 0

Your signature has been erased by a mod because it's larger than 600x120...
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Xolatron old
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Posted: 2nd Sep 2005 05:00
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BatVink, really¿
(1=0) returns 0
(0=0) returns 1
bool = 1
(bool=0) returns 0
bool = 0
(bool=0) returns 1

-Xol


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Neil Young
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Posted: 4th Sep 2005 05:14
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Wow those are great. Thanks! This is why I love programming.
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Xolatron old
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Posted: 4th Sep 2005 06:27
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Yes, me too . There's always a better way, or, for Star Wars fans out there, "There's always a bigger fish."

-Xol


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Jukuma
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Posted: 4th Sep 2005 06:56
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sry, bad code over there from me.
i think the fastes one, if the copilation
asm "lee say dbp makes pure asm code "

null as byte
null = null or %10101010

do

print null and %1

null = null >> 1
wait 1000

loop
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Jukuma
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Posted: 4th Sep 2005 07:12 Edited at: 4th Sep 2005 07:26
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noooooo, ">>" shifting ?? wy don't ">> not rotate the bit's?

before a bad code und now - a sorry again!
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coolgames
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Posted: 26th Sep 2005 21:45
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This will run very fast. It uses a simple equation:

That will switch x between 1 and 0
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coolgames
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Posted: 26th Sep 2005 22:02
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You actually can use pure math to switch between 1 and 0
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