Processing 1.0 - Processing Discourse - Local variable may not have been initialized

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Index › Programming Questions & Help › Syntax Questions › Local variable may not have been initialized

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Local variable may not have been initialized (Read 1189 times)

TVS

Local variable may not have been initialized
Feb 6^th, 2009, 5:16pm

I am trying to run the code as shown below here. I want to use the coordinates of the second node as the coordinates for the first node of the second line, etc etc.
Though I get the error 'Local variable nodeDG2 may not have been initialized".

What causes this, and how can I do this in the right way?
Thanks...

Code:
Node nodeDG1, nodeDG2;
for (int k=0; k<linesCopy.size(); k++) {
L = (Line) linesCopy.get(k);
println("Line["+L.ID1+"]["+L.ID2+"] has angle "+L.getAnglePG());
//nodeDG1 = new Node(L.x1, L.y1, L.ID1);
if (k==0){
nodeDG1 = new Node(L.x1, L.y1, L.ID1);
} else {
println("nodeDG2 X = "+nodeDG2.x);
nodeDG1 = new Node(nodeDG2.x, nodeDG2.y, L.ID1);
}
float dx = sin(L.getAnglePG())*L.getLengthPG();
float dy = cos(L.getAnglePG())*L.getLengthPG();
println("x1 of the line is "+L.x1+" and the x2 of the line is "+(L.x1+dx));
nodeDG2 = new Node( (nodeDG1.x + dx), (nodeDG1.y + dy), L.ID2 );
linesDG.add(new Line(L.ID1, L.ID2, nodeDG1.x, nodeDG1.y, nodeDG2.x, nodeDG2.y));
}

PhiLho

Re: Local variable may not have been initialized
Reply #1 - Feb 6^th, 2009, 5:35pm

As said, you try to use an object that might have not been initialized...
When you declare an object at class level, it is automatically set at null. But if you declare it as local variable, it is undefined.
The workaround is simple: init the variables when declaring them (or before using them):
Node nodeDG1 = null, nodeDG2 = null;
Now, you can have instead a NullPointerException if you use the var before setting it...

TVS YaBB Newbies Offline Posts: 45	Re: Local variable may not have been initialized Reply #2 - Feb 6^th, 2009, 5:38pm Thanks, works as a charm! And about NPE: I understand, and already got that problem a few times before, so I know it by now but thanks anyway ofcourse!

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