Code:
import java.util.Scanner;
/* Class BSTNode */
class BSTNode
{
BSTNode left, right;
int data;
/* Constructor */
public BSTNode()
{
left = null;
right = null;
data = 0;
}
/* Constructor */
public BSTNode(int n)
{
left = null;
right = null;
data = n;
}
/* Function to set left node */
public void setLeft(BSTNode n)
{
left = n;
}
/* Function to set right node */
public void setRight(BSTNode n)
{
right = n;
}
/* Function to get left node */
public BSTNode getLeft()
{
return left;
}
/* Function to get right node */
public BSTNode getRight()
{
return right;
}
/* Function to set data to node */
public void setData(int d)
{
data = d;
}
/* Function to get data from node */
public int getData()
{
return data;
}
}
/* Class BST */
class BST
{
private BSTNode root;
/* Constructor */
public BST()
{
root = null;
}
/* Function to check if tree is empty */
public boolean isEmpty()
{
return root == null;
}
/* Functions to insert data */
public void insert(int data)
{
root = insert(root, data);
}
/* Function to insert data recursively */
private BSTNode insert(BSTNode node, int data)
{
if (node == null)
node = new BSTNode(data);
else
{
if (data <= node.getData())
node.left = insert(node.left, data);
else
node.right = insert(node.right, data);
}
return node;
}
/* Functions to delete data */
public void delete(int k)
{
if (isEmpty())
System.out.println("Tree Empty");
else if (search(k) == false)
System.out.println("Sorry "+ k +" is not present");
else
{
root = delete(root, k);
System.out.println(k+ " deleted from the tree");
}
}
private BSTNode delete(BSTNode root, int k)
{
BSTNode p, p2, n;
if (root.getData() == k)
{
BSTNode lt, rt;
lt = root.getLeft();
rt = root.getRight();
if (lt == null && rt == null)
return null;
else if (lt == null)
{
p = rt;
return p;
}
else if (rt == null)
{
p = lt;
return p;
}
else
{
p2 = rt;
p = rt;
while (p.getLeft() != null)
p = p.getLeft();
p.setLeft(lt);
return p2;
}
}
if (k < root.getData())
{
n = delete(root.getLeft(), k);
root.setLeft(n);
}
else
{
n = delete(root.getRight(), k);
root.setRight(n);
}
return root;
}
/* Functions to count number of nodes */
public int countNodes()
{
return countNodes(root);
}
/* Function to count number of nodes recursively */
private int countNodes(BSTNode r)
{
if (r == null)
return 0;
else
{
int l = 1;
l += countNodes(r.getLeft());
l += countNodes(r.getRight());
return l;
}
}
/* Functions to search for an element */
public boolean search(int val)
{
return search(root, val);
}
/* Function to search for an element recursively */
private boolean search(BSTNode r, int val)
{
boolean found = false;
while ((r != null) && !found)
{
int rval = r.getData();
if (val < rval)
r = r.getLeft();
else if (val > rval)
r = r.getRight();
else
{
found = true;
break;
}
found = search(r, val);
}
return found;
}
/* Function for inorder traversal */
public void inorder()
{
inorder(root);
}
private void inorder(BSTNode r)
{
if (r != null)
{
inorder(r.getLeft());
System.out.print(r.getData() +" ");
inorder(r.getRight());
}
}
/* Function for preorder traversal */
public void preorder()
{
preorder(root);
}
private void preorder(BSTNode r)
{
if (r != null)
{
System.out.print(r.getData() +" ");
preorder(r.getLeft());
preorder(r.getRight());
}
}
/* Function for postorder traversal */
public void postorder()
{
postorder(root);
}
private void postorder(BSTNode r)
{
if (r != null)
{
postorder(r.getLeft());
postorder(r.getRight());
System.out.print(r.getData() +" ");
}
}
}
/* Class BinarySearchTree */
public class BinarySearchTree
{
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
/* Creating object of BST */
BST bst = new BST();
System.out.println("Binary Search Tree Test\n");
char ch;
/* Perform tree operations */
do
{
System.out.println("\nBinary Search Tree Operations\n");
System.out.println("1. insert ");
System.out.println("2. delete");
System.out.println("3. search");
System.out.println("4. count nodes");
System.out.println("5. check empty");
int choice = scan.nextInt();
switch (choice)
{
case 1 :
System.out.println("Enter integer element to insert");
bst.insert( scan.nextInt() );
break;
case 2 :
System.out.println("Enter integer element to delete");
bst.delete( scan.nextInt() );
break;
case 3 :
System.out.println("Enter integer element to search");
System.out.println("Search result : "+ bst.search( scan.nextInt() ));
break;
case 4 :
System.out.println("Nodes = "+ bst.countNodes());
break;
case 5 :
System.out.println("Empty status = "+ bst.isEmpty());
break;
default :
System.out.println("Wrong Entry \n ");
break;
}
/* Display tree */
System.out.print("\nPost order : ");
bst.postorder();
System.out.print("\nPre order : ");
bst.preorder();
System.out.print("\nIn order : ");
bst.inorder();
System.out.println("\nDo you want to continue (Type y or n) \n");
ch = scan.next().charAt(0);
} while (ch == 'Y'|| ch == 'y');
}
}
Output:
Binary Search Tree Test
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
5
Empty status = true
Post order :
Pre order :
In order :
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
1
Enter integer element to insert
8
Post order : 8
Pre order : 8
In order : 8
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
1
Enter integer element to insert
5
Post order : 5 8
Pre order : 8 5
In order : 5 8
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
1
Enter integer element to insert
3
Post order : 3 5 8
Pre order : 8 5 3
In order : 3 5 8
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
1
Enter integer element to insert
7
Post order : 3 7 5 8
Pre order : 8 5 3 7
In order : 3 5 7 8
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
1
Enter integer element to insert
10
Post order : 3 7 5 10 8
Pre order : 8 5 3 7 10
In order : 3 5 7 8 10
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
1
Enter integer element to insert
15
Post order : 3 7 5 15 10 8
Pre order : 8 5 3 7 10 15
In order : 3 5 7 8 10 15
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
1
Enter integer element to insert
2
Post order : 2 3 7 5 15 10 8
Pre order : 8 5 3 2 7 10 15
In order : 2 3 5 7 8 10 15
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
4
Nodes = 7
Post order : 2 3 7 5 15 10 8
Pre order : 8 5 3 2 7 10 15
In order : 2 3 5 7 8 10 15
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
3
Enter integer element to search
24
Search result : false
Post order : 2 3 7 5 15 10 8
Pre order : 8 5 3 2 7 10 15
In order : 2 3 5 7 8 10 15
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
3
Enter integer element to search
7
Search result : true
Post order : 2 3 7 5 15 10 8
Pre order : 8 5 3 2 7 10 15
In order : 2 3 5 7 8 10 15
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
2
Enter integer element to delete
2
2 deleted from the tree
Post order : 3 7 5 15 10 8
Pre order : 8 5 3 7 10 15
In order : 3 5 7 8 10 15
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
2
Enter integer element to delete
8
8 deleted from the tree
Post order : 3 7 5 15 10
Pre order : 10 5 3 7 15
In order : 3 5 7 10 15
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
2
Enter integer element to delete
10
10 deleted from the tree
Post order : 3 7 5 15
Pre order : 15 5 3 7
In order : 3 5 7 15
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
2
Enter integer element to delete
5
5 deleted from the tree
Post order : 3 7 15
Pre order : 15 7 3
In order : 3 7 15
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
2
Enter integer element to delete
15
15 deleted from the tree
Post order : 3 7
Pre order : 7 3
In order : 3 7
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
2
Enter integer element to delete
3
3 deleted from the tree
Post order : 7
Pre order : 7
In order : 7
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
2
Enter integer element to delete
77
Sorry 77 is not present
Post order : 7
Pre order : 7
In order : 7
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
2
Enter integer element to delete
7
7 deleted from the tree
Post order :
Pre order :
In order :
Do you want to continue (Type y or n)
y
Binary Search Tree Operations
1. insert
2. delete
3. search
4. count nodes
5. check empty
5
Empty status = true
Post order :
Pre order :
In order :
Do you want to continue (Type y or n)
n
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