all tasks

Task/Tree-traversal/Java/tree-traversal.java

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+import java.util.Queue;
+import java.util.LinkedList;
+public class TreeTraverse
+{
+ private static class Node<T>
+ {
+  public Node<T> left;
+  public Node<T> right;
+  public T data;
+  public Node(T data)
+  {
+   this.data = data;
+  }
+  public Node<T> getLeft()
+  {
+   return this.left;
+  }
+  public void setLeft(Node<T> left)
+  {
+   this.left = left;
+  }
+  public Node<T> getRight()
+  {
+   return this.right;
+  }
+  public void setRight(Node<T> right)
+  {
+   this.right = right;
+  }
+ }
+ public static void preorder(Node<?> n)
+ {
+  if (n != null)
+  {
+   System.out.print(n.data + " ");
+   preorder(n.getLeft());
+   preorder(n.getRight());
+  }
+ }
+ public static void inorder(Node<?> n)
+ {
+  if (n != null)
+  {
+   inorder(n.getLeft());
+   System.out.print(n.data + " ");
+   inorder(n.getRight());
+  }
+ }
+ public static void postorder(Node<?> n)
+ {
+  if (n != null)
+  {
+   postorder(n.getLeft());
+   postorder(n.getRight());
+   System.out.print(n.data + " ");
+  }
+ }
+ public static void levelorder(Node<?> n)
+ {
+  Queue<Node<?>> nodequeue = new LinkedList<Node<?>>();
+  if (n != null)
+   nodequeue.add(n);
+  while (!nodequeue.isEmpty())
+  {
+   Node<?> next = nodequeue.remove();
+   System.out.print(next.data + " ");
+   if (next.getLeft() != null)
+   {
+    nodequeue.add(next.getLeft());
+   }
+   if (next.getRight() != null)
+   {
+    nodequeue.add(next.getRight());
+   }
+  }
+ }
+ public static void main(final String[] args)
+ {
+  Node<Integer> one = new Node<Integer>(1);
+  Node<Integer> two = new Node<Integer>(2);
+  Node<Integer> three = new Node<Integer>(3);
+  Node<Integer> four = new Node<Integer>(4);
+  Node<Integer> five = new Node<Integer>(5);
+  Node<Integer> six = new Node<Integer>(6);
+  Node<Integer> seven = new Node<Integer>(7);
+  Node<Integer> eight = new Node<Integer>(8);
+  Node<Integer> nine = new Node<Integer>(9);
+  one.setLeft(two);
+  one.setRight(three);
+  two.setLeft(four);
+  two.setRight(five);
+  three.setLeft(six);
+  four.setLeft(seven);
+  six.setLeft(eight);
+  six.setRight(nine);
+  preorder(one);
+  System.out.println();
+  inorder(one);
+  System.out.println();
+  postorder(one);
+  System.out.println();
+  levelorder(one);
+  System.out.println();
+ }
+}