Global Variables driving me crazy!

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FieldDoc

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Joined: 30th May 2003

Location: London, UK

Posted: 8th Jun 2003 15:12

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OK, i'm trying to set some variables at the top of my code so that they can be used by the main code AND functions as well without having to passed to them.

At the top of the code i'm writing something like this:

+ Code Snippet

DIM ActiveBox(1)
ActiveBox(1) = 0
DIM NewCommand(1)
NewCommand(1) = 0
DIM LineNo(1)
LineNo = 0
DIM Spacing(1)
Spacing(1) = 0

However, when I run the program in DeBug mode and look at the values of the variables i'm getting really bizarre numbers allocated to them like '14354360' for example! WTF?!
I wanna be able to use the variables in a function, e.g.:

+ Code Snippet

FUNCTION Hello()
   IF LineNo(1) = 1 THEN PRINT "Hello"
   IF LineNo(1)  THEN PRINT "P**s off!"
ENDFUNCTION

What am I doing wrong?

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When it's soft you can't beat it, when it's hard you get screwed.

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IanM

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Location: In my moon base

Posted: 8th Jun 2003 15:20

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Yes, you can use an array as a global variable - but I find that it's best not to (assuming that you are using DBPro).

Do it like this instead:

+ Code Snippet

global LineNo as integer
LineNo=0

Then use it like this:

+ Code Snippet

function DoStuff()
   if LineNo = 1 then print "Hello"
endfunction

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Rob K

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Location: Surrey, United Kingdom

Posted: 8th Jun 2003 15:33

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@FieldDoc

Arrays are global anyway - there is no need to use the "global" statement on them.

"However, when I run the program in DeBug mode and look at the values of the variables i'm getting really bizarre numbers allocated to them like '14354360' for example! WTF?! "

The debugger cannot read individual values from arrays. What you need to do is to define a global variable of the same type as your array, eg global debug_value

Then when running the debugger, to get a value from an array, go into the CLI (the leftmost tab), type in debug_value = arrayname(index) and then go into the variable watcher and look at debug_value.

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Shadow Robert

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Location: Hertfordshire, England

Posted: 8th Jun 2003 16:12

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+ Code Snippet

dim MyValue(1)
MyValue(1)=10

Hello()
wait key

function Hello()
   if MyValue(1)=10
      print "Ohhh its 10"
   else
      print "Damn... something ain't right"
endfuntion

that will work

+ Code Snippet

MakeArray(10)

Hello()
wait key

function Hello()
   if MyValue(1)=10
      print "Ohhh its 10"
   else
      print "Damn... something ain't right"
endfuntion

function MakeArray( value )
   dim MyValue(1)
   MyValue(1)=value
endfunction

that won't... but we change this

+ Code Snippet

MakeArray(10)

Hello()
wait key

function Hello()
   if MyValue(1)=10
      print "Ohhh its 10"
   else
      print "Damn... something ain't right"
endfuntion

function MakeArray( value )
   global dim MyValue(1)
   MyValue(1)=value
endfunction

and it will again

... its all about understanding how each of the differen variables interact - generally though you should declare values you create as variable types (boolean|byte|word|dword|float|etc...) and also no matter what your doing you should also try to declare it as global or local else it will take it as a standard value operation life ... which is good as it allows you to redeclare these values within functions, but it is also bad as it doesn't globally make sure these values are always declared.

Functions within DBP have been changed to be self contained as opposed to DBv1 where they were globally marked.
This means even though it is possible to have values globally created within the main program, it doesn't guarentee 100% success you can pass them into functions unless you mark them with either Global or Local ... sides it is always good habit to get into declaring everything you use.

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Rob K

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Posted: 8th Jun 2003 16:40

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It pisses me off that you cannot get pointers to arrays though - if you could then I could write a DLL to show those values in a debug window. I believe the arrays are just laid out in a fairly standard way in memory too.

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IanM

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Posted: 8th Jun 2003 17:01

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I know! I've only got one last part to figure out, and I'll know it all. Ha Ha Haaaaaaaaa *head thrown back in evil laugh*

Rob, drop me an email, and I'll let you have all the info I have on arrays. It'll be tonight though, coz I'm off out now.

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FieldDoc

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Location: London, UK

Posted: 8th Jun 2003 22:36

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Thanks guys....the GLOBAL command works perfectly! I was only using arrays coz the recommended book said to....perhaps it was refering to DBC?

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Bighead

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Posted: 8th Jun 2003 23:39

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@Raven:

I had to change the order of the functions included in your last script:

+ Code Snippet

MakeArray(10)

Hello()
wait key

function MakeArray( value )
   global dim MyValue(1)
   MyValue(1)=value
endfunction

function Hello()
   if MyValue(1)=10
      print "Ohhh its 10"
   else
      print "Damn... something ain't right"
   endif
endfunction

... otherwise I get the following error message:

#100044: Cannot find structure 'Hello:MyValue' in local declaration at line 7.

(still, your script runs and the else piece of code is selected)

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