Quickie, global variables and sub functions.

Hi,

I have a primary function set with 12 global variables I want the sub-functions to use, they are only double constants held during a loop.

Apart from being typing lazy (copy/past) and prob bad programming, is there any programming problem or reason why I should not declare a global variable in a sub-function that is not used?

Thanks

AD

Answer 1

[Paulo Silva]

The variables should be passed to the functions as arguments, using global variables always introduce problems that are hard to debug, also if you declare a variable on a function you can access the same variable in every sub-function of that function.

Now for your question, besides the use of global variables and that sub-function that's not used?! I don't see any other problem

[Sean de Wolski]

+1, but I think you meant nested functions can see the variables, subfunctions need them to be passed in.

[Paulo Silva]

Sean you are correct, thanks, I always confuse them, there's a nice video tutorial from Doug Hull http://blogs.mathworks.com/videos/2011/09/20/managing-code-in-matlab-nested-sub-functions

[Scragmore]

Thanks, it was as I thought. Laziness on my part, not wanting to custom build large passes to a function. As well as readability and good programing practice. I think I managed to look for a compromise, declaring global sudo constants for large scale function structures and passing local variables.

Thanks for the clarification.

AD