Hi there,

I am having difficulty running this code and can't figure out why. The fourth nested loop doesn't seem to want to iterate. Also, I get the following null pointer exception:

java.lang.NullPointerException

at processing.core.PApplet.displayable(PApplet.java:8345)

at processing.app.Runner.startInternal(Runner.java:351)

at processing.app.Runner.start(Runner.java:79)

at processing.app.Editor.handleRun(Editor.java:1112)

at processing.app.EditorToolbar.mousePressed(EditorToolbar.java:316)

at java.awt.Component.processMouseEvent(Unknown Source)

at javax.swing.JComponent.processMouseEvent(Unknown Source)

at java.awt.Component.processEvent(Unknown Source)

at java.awt.Container.processEvent(Unknown Source)

at java.awt.Component.dispatchEventImpl(Unknown Source)

at java.awt.Container.dispatchEventImpl(Unknown Source)

at java.awt.Component.dispatchEvent(Unknown Source)

at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)

at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)

at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)

at java.awt.Container.dispatchEventImpl(Unknown Source)

at java.awt.Window.dispatchEventImpl(Unknown Source)

at java.awt.Component.dispatchEvent(Unknown Source)

at java.awt.EventQueue.dispatchEvent(Unknown Source)

at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)

at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)

at java.awt.EventDispatchThread.pumpEvents(Unknown Source)

at java.awt.EventDispatchThread.pumpEvents(Unknown Source)

at java.awt.EventDispatchThread.run(Unknown Source)

Which I don't really understand. Here is the code that I used..... Is the syntax ok? Why is it crashing? Any ideas?

final int TOTINV = 4;
final int PERMS = 35;
int[][] vec = new int[PERMS][TOTINV];
int counter;
boolean initted = false;
PrintWriter output;

void setup(){
output = createWriter("perms.txt");
for(int x = 0; x < PERMS; x++){
 for(int y = 0; y < TOTINV; y++){
   vec[x][y]=0;
 }
}
}

void main(){
 if (!initted){
   init();
   initted = true;
 }else{
   output.flush();
   output.close();
   println("finished");
   exit();
 }
}

void init(){
 counter = 0;
 for(int i = 0; i < TOTINV+1; i++){
   for(int j = 0; j < TOTINV+1; j++){
     for(int k = 0; k < TOTINV+1; k++){
       for(int m = 0; m < TOTINV+1; m++){
         println(i + ":" + j + ":" + k + ":" + m);
         if((i+j+k+m) == 4){
           vec[counter][0]= i;
           vec[counter][1]= j;
           vec[counter][2]= k;
           vec[counter][3]= m;
           println(counter +": " + vec[counter][0] + ", " + vec[counter][1] + ", " + vec[counter][2] + ", " + vec[counter][3]);
           //output.println(counter +": " + vec[counter][0] + ", " + vec[counter][1] + ", " + vec[counter][2] + ", " + vec[counter][3]);
           counter++;
         }else{
           break;
         }
       }
     }
   }
 }
}

Thank you Ben. Changing the names of init() and main() got rid of the null pointer exception and the program runs now. However I am still puzzled why the program doesn't seem to iterate through my innermost for loop. Any ideas why anyone?