velox
Retired
How can altering the scope of a variable, be used to allow other modules access to required data items?
Any ideas?
Any ideas?
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Variables (1 Viewer)
- Thread starter velox
- Start date
The scope of a variable refers to which parts of the program can have access to it, for example Public, Private, Dim in visual basic. if the scope was changed to public then it can be globally accessed within the same solution.
velox
Retired
ah ic, i was a bit lost on the scope part. Cool thank u! I have another question though 
Procedures and functions are different types of subprograms. What is the difference between the two in terms of how they are called by higher-level routines?
Procedures and functions are different types of subprograms. What is the difference between the two in terms of how they are called by higher-level routines?
Well procedures do a certain task, it does blah blah and that's it, then returns control back to the caller, for functions, they provide a return value generally, just like maths, you know f(x) is a function, and when you sub in x, you'd get y, right?
hmmm i'm not sure about the higher-level routines bit.
hmmm i'm not sure about the higher-level routines bit.
velox
Retired
Got it now. You said the same thing as what the textbook was saying. thanks
velox
Retired
Lol You are in the book though. "Winston" is a ficticious language in there somewhere.
velox
Retired
I have another question What exactly does this algorithm do. I tried to follow it but ended up getting lost.
Public Sub DrawLines(Numlines As Integer)
Dim Coord (1, 1) As Integer
Dim CurrentLine as Integer
Randomise Timer
Coord(0, 0) = 0
Coord(0, 1) = 0
CurrentLine = 1
While CurrentLine < Numlines
Coord (0, 1) = Int(Me.Width * Rnd)
Me.Line (Coord(0, 0), Coord(0,1))-(Coord(1,0), Coord(1, 1))
Coord(0, 0) = Coord(1,0)
Coord(0, 1) = Coord(1, 1)
CurrentLine = CurrentLine + 1
Wend
End Sub
Do u think it would be suitable for inclusion into a library of code? Or is it too specific?
What exactly does this algorithm do. I tried to follow it but ended up getting lost. Public Sub DrawLines(Numlines As Integer)
Dim Coord (1, 1) As Integer
Dim CurrentLine as Integer
Randomise Timer
Coord(0, 0) = 0
Coord(0, 1) = 0
CurrentLine = 1
While CurrentLine < Numlines
Coord (0, 1) = Int(Me.Width * Rnd)
Me.Line (Coord(0, 0), Coord(0,1))-(Coord(1,0), Coord(1, 1))
Coord(0, 0) = Coord(1,0)
Coord(0, 1) = Coord(1, 1)
CurrentLine = CurrentLine + 1
Wend
End Sub
Do u think it would be suitable for inclusion into a library of code? Or is it too specific?
Hmm.. That code looks a bit buggy - where did you get it from. It looks like it is supposed to draw a number (NumLines) of lines starting from the origin. i.e the origin to some point in the form, then another line from the other end of that line and so on... Maybe it is supposed to have:
Coord(1, 0) = Int(Me.Width * Rnd)
Coord(1, 1) = Int(Me.Height * Rnd)
Instead of just:
Coord (0, 1) = Int(Me.Width * Rnd)
Also, you may have to change the datatype of Coord to Long, as Integer may be a bit too small. And, randomize doesn't have an 's' (at least not in VB) and i don't think you need the word 'Timer' either.
Coord(1, 0) = Int(Me.Width * Rnd)
Coord(1, 1) = Int(Me.Height * Rnd)
Instead of just:
Coord (0, 1) = Int(Me.Width * Rnd)
Also, you may have to change the datatype of Coord to Long, as Integer may be a bit too small. And, randomize doesn't have an 's' (at least not in VB) and i don't think you need the word 'Timer' either.
Last edited:
velox
Retired
Its a question from a textbook ....
The code is VB6, it's question 14 of Set 5D in my SDD prelim text. However it has not been copied correctly from the text (as JOn quite rightly points out). JOn's corrections are essentially correct as is his description of what the algorithm does.
Here's the original:
Public Sub DrawLines(Numlines As Integer)
Dim Coord(1, 1) As Integer
Dim CurrentLine As Integer
Randomize Timer
Coord(0, 0) = 0
Coord(0, 1) = 0
CurrentLine = 1
While CurrentLine < Numlines
Coord(1, 0) = Int(Me.Width * Rnd)
Coord(1, 1) = Int((Me.Height - 500) * Rnd)
Me.Line (Coord(0, 0), Coord(0, 1))-(Coord(1, 0), Coord(1, 1))
Coord(0, 0) = Coord(1, 0)
Coord(0, 1) = Coord(1, 1)
CurrentLine = CurrentLine + 1
Wend
End Sub
Actually an Integer datatype is within the bounds of most screens. Integers range up to 32767 and by default VB6 uses twips. 1024 pixels equates to some 15480 twips (in VB6), so you'd need to use a screen resolution greater than about 2000 pixels wide to run into problems.
HTH
Sam
Here's the original:
Public Sub DrawLines(Numlines As Integer)
Dim Coord(1, 1) As Integer
Dim CurrentLine As Integer
Randomize Timer
Coord(0, 0) = 0
Coord(0, 1) = 0
CurrentLine = 1
While CurrentLine < Numlines
Coord(1, 0) = Int(Me.Width * Rnd)
Coord(1, 1) = Int((Me.Height - 500) * Rnd)
Me.Line (Coord(0, 0), Coord(0, 1))-(Coord(1, 0), Coord(1, 1))
Coord(0, 0) = Coord(1, 0)
Coord(0, 1) = Coord(1, 1)
CurrentLine = CurrentLine + 1
Wend
End Sub
Actually an Integer datatype is within the bounds of most screens. Integers range up to 32767 and by default VB6 uses twips. 1024 pixels equates to some 15480 twips (in VB6), so you'd need to use a screen resolution greater than about 2000 pixels wide to run into problems.
HTH
Sam
velox
Retired
Im now thinking that it would be suitable for inclusion into a library of code, as it could be put to many uses (yet to think of any ). Am I thinking in the right direction?
). Am I thinking in the right direction?For inclusion in a library of code it needs to be totally general in terms of its interface and it needs to deal with any errors that could be encountered. In other words it should be able to be used without knowing how it works just what it does.
It's almost right, however if you were to add this Sub to a VB6 module it would NOT quite work, the use of Me will cause problems. You'd need to pass the form as a parameter to the Sub and then it should work from a module. It also needs some code for dealing with errors.
Why you would want to draw lines all over a form is another issue. I'm fishing a bit, but maybe you could use it to indicate an error has occured, or with some modification it could be used as an indicator that background processing is occuring.
HTH
Sam
It's almost right, however if you were to add this Sub to a VB6 module it would NOT quite work, the use of Me will cause problems. You'd need to pass the form as a parameter to the Sub and then it should work from a module. It also needs some code for dealing with errors.
Why you would want to draw lines all over a form is another issue. I'm fishing a bit, but maybe you could use it to indicate an error has occured, or with some modification it could be used as an indicator that background processing is occuring.
HTH
Sam
