how i can implement these methods:

public int level(T el) { return level(el, root); } protected int level(T el, BSTNode p) { if(p == null) { return -1; } if(p.key.equals(el)) { return 1; } int l = level(el, p.left); int r = level(el, p.right); if(l != -1) { return 1 + l; } else if(r != -1) { return 1 + r; } else { return -1; } } public boolean isDecisionTree() { return isDecisionTree(root); } protected boolean isDecisionTree(BSTNode p) { if(p == null || (p.left == null && p.right == null)) { return true; } else if(p.left != null && p.right != null){ return isDecisionTree(p.left) && isDecisionTree(p.right); } else { return false; } } public int getPathLength(T el) { return getPathLength(el, root); } protected int getPathLength(T el, BSTNode p) { if(p == null) { return -1; } if(p.key.equals(el)) { return 0; } int l = getPathLength(el, p.left); int r = getPathLength(el, p.right); if(l != -1) { return 1 + l; } else if(r != -1) { return 1 + r; } else { return -1; } }

in this class :

import java.util.Scanner;

import java.util.*;

public class TestIntegerBST {

public static void main (String[] args){

BST tree = new BST();

int option, target;

Scanner reader = new Scanner(System.in);

do {

System.out.println(" ***************************");

System.out.println("* Testing Binary Search Tree *");

System.out.println("*************************** ");

System.out.println("1. Insert an element");

System.out.println("2. Search for an element");

System.out.println("3. Delete an element");

System.out.println("4. Print in Breadth-First-Order");

System.out.println("5. Print in Pre-Order");

System.out.println("6. Print in In-Order");

System.out.println("7. Print in Post-Order");

System.out.println("8. Print sum of the elements");

System.out.println("9. Quit");

System.out.print(" Select an Option [1...9] : ");

option = reader.nextInt();

switch (option) {

case 1 : System.out.print("Enter the element to insert: ");

tree.insert(reader.nextInt());

break;

case 2 : System.out.print("Enter the element to search for: ");

target = reader.nextInt();

Integer result = tree.search(target);

if (result != null)

System.out.println("Element, "+result+ " was found in the tree");

else

System.out.println("Sorry, the element was not found");

break;

case 3 : System.out.print("Enter the element delete: ");

tree.delete(reader.nextInt());

break;

case 4 : tree.breadthFirst();

break;

case 5 : tree.preorder();

break;

case 6 : tree.inorder();

break;

case 7 : tree.postorder();

break;

case 8 : System.out.print("Sum of the elements in the tree is: "+sum(tree));

break;

} //end of switch

} while (option != 9);

} //end of main

public static int sum(BST tree) {

int sum = 0;

for (int n : tree)

sum += n;

return sum;

}

}