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Index › Programming Questions & Help › Syntax Questions › param () and global variables
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param () and global variables (Read 449 times)
EtienneR
param () and global variables
May 23rd, 2006, 4:16pm  
Hello,

(this is while programming in continuous mode)

I have an Array, needed as a global variable, thus declared before setup() and draw(). Its size is recieved from a website, thanks to param (). When calling param() outside setup() and draw(), it doesn't work (unexpected token void, pointing at the setup () ).

How can we manage that ?
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fjen
Re: param () and global variables
Reply #1 - May 23rd, 2006, 4:27pm  
declare outside of any classes / methods, then initialize inside:
Code:

int[] wh;
void setup()
{
    int _w = Integer.parseInt(param("myWidth"));
    int _h = Integer.parseInt(param("myHeight"));
    wh = new int[]{ _w, _h };
    // ...
}

F
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fjen
Re: param () and global variables
Reply #2 - May 23rd, 2006, 4:42pm  
i should add:

the initialization of varibles or objects in "global" (PApplet) scope may happen at any time. so before you use them you have to either make sure they have been initialized or initialize them at that point. good practice would be to use setup() for that, since that's what it is meant for ...

F
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EtienneR
Re: param () and global variables
Reply #3 - May 23rd, 2006, 4:58pm  
OK thanks, it works fine Smiley

You're right concerning the methodology, it seems much cleaner like this; but I don't know why, I was convinced I had to set the size of the array when declaring it.
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