Problems with global variables

I'm willing to use the global function to define some constant parameters in a structure. The written codes are as following

But according to the error reminder the current use of 'Biofilm' is inconsistent with the previous use or Definition. I couldn't understand this hint and still couldn't find the error. Could anyone help me with that? Thanks a lot!

[Guillaume]

As a rule, don't use global variables.

Why does Biofilm need to be global? It is already defined as a normal variable since it is an output of the function. It looks like you either don't understand what global variables are, or how functions work.

[Jacob Bean]

Regardless of his level of understanding, people come here to ask questions. Not to be ridiculed.

[Guillaume]

@Jacob, I'm not sure who your comment is addressed to. Nobody was being ridiculed in my post. There was a piece of advice and a genuine question that would have helped answering the OP question, had that question been answered.

Answer 1

[Krishna Bindumadhavan]

You may have to remove Biofilm as the return argument, to make the function signature look like:

function setGlobalbiofilm()

As Biofilm is a global variable , it does not seem to be possible to declare it as a return value of a function. You can take a look at this documentation for further information.