Not working

src/Simulation.java

@@ -1,8 +1,80 @@
+import codedraw.CodeDraw;
+
+import java.awt.*;
+import java.util.Random;
+
 public class Simulation {
 
+    // gravitational constant
+    public static final double G = 6.6743e-11;
+
+    // one astronomical unit (AU) is the average distance of earth to the sun.
+    public static final double AU = 150e9; // meters
+
+    // one light year
+    public static final double LY = 9.461e15; // meters
+
+    // some further constants needed in the simulation
+    public static final double SUN_MASS = 1.989e30; // kilograms
+    public static final double SUN_RADIUS = 696340e3; // meters
+    public static final double EARTH_MASS = 5.972e24; // kilograms
+    public static final double EARTH_RADIUS = 6371e3; // meters
+
+    // set some system parameters
+    public static final double SECTION_SIZE = 2 * AU; // the size of the square region in space
+    public static final int NUMBER_OF_BODIES = 22;
+    public static final double OVERALL_SYSTEM_MASS = 20 * SUN_MASS; // kilograms
+
     public static void main(String[] args) {
-        //TODO: please use this class to run your simulation
+        CodeDraw cd = new CodeDraw();
+        Body[] bodies = new Body[NUMBER_OF_BODIES];
 
+        Random random = new Random(2022);
+
+        for (int i = 0; i < Simulation.NUMBER_OF_BODIES; i++) {
+            bodies[i] = new Body(
+                    Math.abs(random.nextGaussian()) * Simulation.OVERALL_SYSTEM_MASS / Simulation.NUMBER_OF_BODIES,
+                    new Vector(
+                            0.2 * random.nextGaussian() * Simulation.AU,
+                            0.2 * random.nextGaussian() * Simulation.AU,
+                            0.2 * random.nextGaussian() * Simulation.AU
+                    ),
+                    new Vector(
+                            0 + random.nextGaussian() * 5e3,
+                            0 + random.nextGaussian() * 5e3,
+                            0 + random.nextGaussian() * 5e3
+                    )
+            );
+        }
+
+        long seconds = 0;
+        while (true) {
+            seconds++;
+
+            /*
+            BodyLinkedList mergedBodies = new BodyLinkedList();
+            for (Body b1 : bodies) {
+                BodyLinkedList colliding = bodies.removeCollidingWith(b1);
+                for (Body b2 : colliding) {
+                    b1 = b1.merge(b2);
+                }
+                mergedBodies.addLast(b1);
+            }
+            bodies = mergedBodies;
+            */
+            Octree octree = new Octree(new Vector(AU), SECTION_SIZE);
+            for (Body body : bodies) {
+                octree.add(body);
+            }
+            octree.applyForces(bodies, 1);
+
+            if ((seconds % 3600) == 0) {
+                cd.clear(Color.BLACK);
+                for (Body body : bodies) {
+                    body.draw(cd);
+                }
+                cd.show();
+            }
+        }
     }
-
 }