I have added Binary Search Tree Program

BST.cpp

@@ -0,0 +1,280 @@
+#include <iostream>
+using namespace std;
+struct BST
+{
+    int id;
+    BST *left = NULL, *right = NULL;
+};
+BST *root = NULL;
+void insertNode(BST *curr)
+{
+    if (root == NULL)
+    {
+        root = curr;
+    }
+    else
+    {
+        BST *p = root, *q = NULL;
+        while (p != NULL)
+        {
+            q = p;
+            if (p->id >curr->id)
+            {
+                p = p->left;
+            }
+            else
+            {
+                p = p->right;
+            }
+        }
+        if (q->id >curr->id)
+        {
+            q->left = curr;
+        }
+        else
+        {
+            q->right = curr;
+        }        
+    }
+}
+void autoFillBST()
+{
+    int arr[] = {80, 60, 100, 110, 200, 210, 105, 50, 20, 40, 65, 75, 82, 84, 85};
+    int size = 15;
+    for (int i = 0; i < size; i++)
+    {
+        BST *curr = new BST; curr->id = arr[i];
+        insertNode(curr);
+    }
+    cout<<"\nBinary Search Tree Constructed"<<endl;
+}
+void inorderTraversal(BST *p)
+{
+    if (p!=NULL)
+    {
+        inorderTraversal(p->left);
+        cout<<"ID: "<<p->id<<endl;
+        inorderTraversal(p->right);
+    }
+}
+void postOrderTraversal(BST *p)
+{
+    if (p!=NULL)
+    {
+        inorderTraversal(p->left);
+        inorderTraversal(p->right);
+        cout<<"ID: "<<p->id<<endl;
+    }   
+}
+void preOrderTraversal(BST *p)
+{
+    if (p!=NULL)
+    {
+        cout<<"ID: "<<p->id<<endl;
+        inorderTraversal(p->left);
+        inorderTraversal(p->right);
+    }
+}
+BST* searchNode(int key)
+{
+    BST *p = root;
+    while (p!=NULL)
+    {
+        if(p->id == key)
+        {
+            return p;
+        }
+        else if (p->id > key)
+        {
+            p = p->left;
+        }
+        else
+        {
+            p = p->right;
+        }
+    }
+    return NULL;
+}
+
+BST* rightLeastNode(BST *p)
+{
+    while (p->left!=NULL)
+    {
+        cout<<"Finding right least value: "<<p->id<<endl;
+        p = p->left;
+    }
+    cout<<"Finding right least value: "<<p->id<<endl;
+    return p;
+}
+void deleteNode(BST *nodeToDelete)
+{
+    if (nodeToDelete->left !=NULL && nodeToDelete->right != NULL)
+    {
+        BST *rightLeast = rightLeastNode(nodeToDelete->right);
+        nodeToDelete->id = rightLeast->id;
+        cout<<"Found node to delete: "<<nodeToDelete->id<<endl;
+        BST *p = nodeToDelete->right;
+        while (p != rightLeast)
+        {
+            cout<<"Finding the node to delete: "<<p->id<<endl;
+            p = p->left;
+        }
+        cout<<"Finding the node to delete: "<<p->id<<endl;
+        if (p != NULL && p == rightLeast)
+        {
+            deleteNode(p);
+        }
+        cout<<" node after deletion: "<<p->id<<endl;
+    }
+    else if (nodeToDelete->left != NULL && nodeToDelete->right == NULL)
+    {
+        nodeToDelete->id = nodeToDelete->left->id;
+        nodeToDelete->left = nodeToDelete->left->left;
+    }
+    else if (nodeToDelete->left == NULL && nodeToDelete->right != NULL)
+    {
+        nodeToDelete->id = nodeToDelete->right->id;
+        nodeToDelete->right = nodeToDelete->right->right;
+    }
+    else
+    {
+        delete nodeToDelete; nodeToDelete = NULL;
+    }
+}
+int countleaf = 0; //variable which will store num of leaf NODES
+void countLeafNodes(BST *p)
+{
+    if (p!=NULL)
+    {
+        if(p->left== NULL&&p->right ==NULL)
+        {
+            countleaf++;
+        }
+
+        countLeafNodes(p->left);
+        countLeafNodes(p->right);
+    }
+}
+int count = 0; //variable which will store number of NODES
+void countNumOfNodes(BST *p)
+{
+    if (p!=NULL)
+    {
+        count++;
+        countNumOfNodes(p->left);
+        countNumOfNodes(p->right);
+    }
+}
+int max(int leftHeight, int rightHeight)
+{
+    if (leftHeight > rightHeight)
+    {
+        return leftHeight;
+    }
+    return rightHeight;
+}
+int findHeight(BST *p)
+{
+    if (p == NULL)
+    {
+        return -1;
+    }
+    int leftHeight = findHeight(p->left);
+    int rightHeight = findHeight(p->right);
+
+    return max(leftHeight, rightHeight) + 1;
+}
+void opt()
+{
+    cout<<"\n1- Insert a Node"<<endl
+        <<"2- AutoFill BST"<<endl
+        <<"3- Delete a Node"<<endl
+        <<"4- Search a Node"<<endl
+        <<"5- InOrder Traversal of Tree"<<endl
+        <<"6- PreOrder Traversal of Tree"<<endl
+        <<"7- PostOrder Traversal of Tree"<<endl
+        <<"8- Count Nodes of Tree"<<endl
+        <<"9- Count Nodes at Right of Tree"<<endl
+        <<"10- Count Leaf Nodes of Tree"<<endl
+        <<"11- Find Height of Tree"<<endl
+        <<"0- Terminate the Program"<<endl;
+
+    cout<<"Enter your Choice: ";
+    int choice; cin>>choice;
+
+    switch (choice)
+    {
+    case   1:
+        cout<<"\nINSERT A NODE METHOD"<<endl;
+        BST *curr; curr = new BST;
+        cout<<"Enter a id: "; cin>>curr->id;
+        insertNode(curr); opt(); break;
+
+    case   2:
+        cout<<"\nAUTOFILL BST METHOD"<<endl;
+        autoFillBST(); opt(); break;
+
+    case   3:
+        cout<<"\nDELETE A NODE METHOD"<<endl;
+        cout<<"Enter id of Node to Delete: "; int val; cin>>val;
+        BST *nodeToDelete; nodeToDelete = searchNode(val);
+        deleteNode(nodeToDelete); opt(); break;
+
+    case   4:
+        cout<<"\nSEARCH A NODE METHOD"<<endl;
+        cout<<"Enter id to Search: "; int key; cin>>key;
+        if (searchNode(key) != NULL)
+        {
+            cout<<"Id found: "<<searchNode(key)->id<<endl;
+        }
+        else
+        {
+            cout<<"Id not found"<<endl;
+        }
+        opt(); break;
+
+    case   5:
+        cout<<"\nINORDER TRAVERSAL OF TREE METHOD"<<endl;
+        inorderTraversal(root); opt(); break;
+
+    case   6:
+        cout<<"\nPREORDER TRAVERSAL OF TREE METHOD"<<endl;
+        preOrderTraversal(root); opt(); break;
+
+    case   7:
+        cout<<"\nPOSTORDER TRAVERSAL OF TREE METHOD"<<endl;
+        postOrderTraversal(root); opt(); break;
+
+    case   8:
+        cout<<"\nCOUNT NODES OF TREE METHOD"<<endl;
+        countNumOfNodes(root);
+        cout<<"Number of Nodes in Tree is: "<<count<<endl; opt(); break;
+
+    case   9:
+        cout<<"\nCOUNT NODES at RIGHT OF TREE METHOD"<<endl;
+        countNumOfNodes(root->right);
+        cout<<"Number of Nodes at right of Tree is: "<<count<<endl; opt(); break;
+
+    case   10:
+        cout<<"\nCOUNT LEAF NODE OF TREE METHOD"<<endl;
+        countLeafNodes(root);
+        cout<<"Number of Leaf Nodes of Tree is: "<<countleaf<<endl; opt(); break;
+
+    case   11:
+        cout<<"\nFIND HEIGHT OF TREE METHOD"<<endl;
+        cout<<"Height of Tree is: "<<findHeight(root)<<endl; opt(); break;
+
+    case   0:
+        cout<<"\nProcess Terminated Successfully"<<endl;
+        break;
+
+    default:
+        cout<<"INVALID CHOICE TRY AGAIN!!"<<endl;
+        opt(); break;
+    }
+}
+int main()
+{
+    opt();
+    return 0;
+}