Boolean problem, and solution (sort of)

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Ratty Rat

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Posted: 26th Feb 2003 15:13

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The following code should tell you the value of the boolean in the type:-

+ Code Snippet

TYPE enemy
   b as boolean
ENDTYPE

DIM enemies( 0 ) AS enemy

enemies( 0 ).b = 0
if enemies( 0 ).b then Print "ITS TWU ITS TWU"
if not enemies( 0 ).b then Print "ITS NOT TWU ITS NOT TWU"

wait key

It works with the boolean set to 1, if its zero it shows both answers (weird).
The following variation fixes it:-

+ Code Snippet

TYPE enemy
   b as boolean
ENDTYPE

DIM enemies( 0 ) AS enemy

enemies( 0 ).b = 0
if 1 and enemies( 0 ).b then Print "ITS TWU ITS TWU"
if 0 and not enemies( 0 ).b then Print "ITS NOT TWU ITS NOT TWU"

wait key

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The Big Babou

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Posted: 26th Feb 2003 15:28

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i'm still thinking about the problem with the first code snippet, but for the second one:
0 and variable always returns 0, variable and variable2 returns 1 when both variables are 1

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MrTAToad

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Posted: 26th Feb 2003 15:43

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I think there is a problem with boolean variables anyway - try it with, say, integers and see what happens.

Good news everyone! I really am THAT good...
http://www.nickk.nildram.co.uk/ for great plug-ins - oh my, yes!

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The Big Babou

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Posted: 26th Feb 2003 15:53

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perhaps kind of bug

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Shadow Robert

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Posted: 26th Feb 2003 16:19

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personally i'd write it

+ Code Snippet

TYPE enemy
   b as boolean
ENDTYPE

DIM enemies( 0 ) AS enemy

enemies( 0 ).b = 0
if enemies( 0 ).b = 1 
   Print "ITS TWU ITS TWU"
else
   Print "ITS NOT TWU ITS NOT TWU"
endif

wait key

to me it doesn't seem like a bug because DarkBasic doesn't have an automatic TRUE / FALSE indication with variables (and why should it?)

Tsu'va Oni Ni Jyuuko Fiori Sei Tau!
One block follows the suit ... the whole suit of blocks is the path ... what have you found?

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Ratty Rat

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Posted: 26th Feb 2003 17:19

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Raven - Try changing the boolean to 1, your way does not work.

TheBigBabou - I see what your saying, IE that a boolean 'AND' would return 0, however it obviously does not or else the second print would never get run, which is does when the boolean is zero.

MrTAToad - Works fine with integers (using Ravens method that is) but in theory using true booleans should be quicker.

Incidentally (and with a nod to Raven here) this works too:-

+ Code Snippet

TYPE enemy
   b as boolean
ENDTYPE

DIM enemies( 0 ) AS enemy

enemies( 0 ).b = 1
`if 1 and enemies( 0 ).b then Print "ITS TWU ITS TWU"
if not enemies( 0 ).b
   Print "ITS NOT TWU ITS NOT TWU"
else
   Print "ITS TWU ITS TWU"
endif

wait key

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MrTAToad

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Posted: 26th Feb 2003 18:05

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Indeed it should be better with booleans, which makes me think the boolean type is bugged...

Good news everyone! I really am THAT good...
http://www.nickk.nildram.co.uk/ for great plug-ins - oh my, yes!

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Shadow

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Posted: 26th Feb 2003 23:48

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I had a problem with booleans

e.g.

Doesn't text "exist" ever

+ Code Snippet

type whatever
 exist as boolean
 field2 as integer
endtype

dim win(255) as whatever

win(1).exist=1

if win(1).exist
print "EXIST"
endif

whereas this prints even when it's not supposed to:

+ Code Snippet

type whatever
 exist as boolean
 field2 as integer
endtype

dim win(255) as whatever

win(1).exist=1

if win(1).exist=1
print "EXIST"
endif

The only way around it was to set an integer equal to the boolean, e.g.

integer1=win(1).exist

and then check if the integer equalled 1, e.g.

if integer1
print "exist"
endif

OR

if integer1=1
print "exist"
endif

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Shadow Robert

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Posted: 27th Feb 2003 02:19

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i wonder why these problems never arrose for fmtBSP as i check the boolean value of the binary in a similar way

you know i think perhaps we need more precise operators
like adding == for boolean match and such ... but then again maybe it because i'm not actually using a boolean value, i'm checking a bytes boolean value - but still use a boolean to check it against. ho hum eh

Tsu'va Oni Ni Jyuuko Fiori Sei Tau!
One block follows the suit ... the whole suit of blocks is the path ... what have you found?

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DarkBASIC Professional Discussion / Boolean problem, and solution (sort of)