// Class to represent a generic binary search tree
public class SearchTree<E extends Comparable<E>> {
   private TreeNode<E> overallRoot;
   
   public SearchTree() {
      this.overallRoot = null;
   }
   
   // adds the given value to this binary search tree
   public void add(E value) {
      overallRoot = add(value, overallRoot);
   }
   
   // adds the given value to the binary seach tree beginning
   //   at the given root
   private TreeNode<E> add(E value, TreeNode<E> root)  {
      if (root == null) {
         root = new TreeNode<E>(value);
      } else if (value.compareTo(root.data) > 0) {
         root.right = add(value, root.right);
      } else if (value.compareTo(root.data) < 0) {
         root.left = add(value, root.left);
      }
      return root;
   }
   

   // prints this tree using preorder traversal
   public void printPreorder() {
      System.out.print("preorder: ");
      printPreorder(overallRoot);
      System.out.println();
   }
   
   // prints the tree with the given root using preorder traversal
   private void printPreorder(TreeNode<E> root) {
      if (root != null) {
         System.out.print(" " + root.data);
         printPreorder(root.left);
         printPreorder(root.right);
      }
   }
   
   // prints this tree using inorder traversal   
   public void printInorder() {
      System.out.print("inorder: ");
      printInorder(overallRoot);
      System.out.println();
   }

   // prints the tree with the given root using inorder traversal   
   private void printInorder(TreeNode<E> root) {
      if (root != null) {
         printInorder(root.left);
         System.out.print(" " + root.data);
         printInorder(root.right);
      }
   }
   
   // prints this tree using postorder traversal   
   public void printPostorder() {
      System.out.print("postorder: ");
      printPostorder(overallRoot);
      System.out.println();
   }   
   
   // prints the tree with the given root using postorder traversal   
   private void printPostorder(TreeNode<E> root) {
      if (root != null) {
         printPostorder(root.left);
         printPostorder(root.right);
         System.out.print(" " + root.data);
      }
   }      



   
   // prints the contents of this tree, one per line, 
   //   using indentation to indicate depth
   // output will look like this tree rotated 90 degrees
   public void printSideways() {
      printSideways(overallRoot, 0);
   }
   
   // prints the contents of the tree with the given root
   //   indenting each line to at least the given level
   private void printSideways(TreeNode<E> root, int level) {
      if (root != null) {
         printSideways(root.right, level + 1);
         for (int i = 0; i < level; i++) {
            System.out.print("    ");
         }
         System.out.println(root.data);
         printSideways(root.left, level + 1);
      }
   }   
}