Lab10.c

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
struct BST
{
    int data;
    struct BST *lchild;
    struct BST *rchild;
};
typedef struct BST *NODE;
NODE get_node()
{
    NODE temp;
    temp = (NODE)malloc(sizeof(struct BST));
    temp->lchild = NULL;
    temp->rchild = NULL;
    return temp;
}
void insert(NODE root, NODE newnode);
void inorder(NODE root);
void preorder(NODE root);
void postorder(NODE root);
void search(NODE root, int key);
void insert(NODE root, NODE newnode)
{
    /*Note: if newnode->data == root->data it will be skipped. No duplicate nodes are allowed */
    if (newnode->data < root->data)
    {
        if (root->lchild == NULL)
            root->lchild = newnode;
        else

            insert(root->lchild, newnode);
    }
    if (newnode->data > root->data)
    {
        if (root->rchild == NULL)
            root->rchild = newnode;
        else
            insert(root->rchild, newnode);
    }
}
void search(NODE root, int key)
{
    NODE cur;
    if (root == NULL)
    {
        printf("\nBST is empty.");
        return;
    }
    cur = root;
    while (cur != NULL)
    {
        if (cur->data == key)
        {
            printf("\nKey element %d is present in BST", cur->data);
            return;
        }
        if (key < cur->data)
            cur = cur->lchild;
        else
            cur = cur->rchild;
    }
    printf("\nKey element %d is not found in the BST", key);
}

void inorder(NODE root)
{
    if (root != NULL)
    {
        inorder(root->lchild);
        printf("%d ", root->data);
        inorder(root->rchild);
    }
}

void preorder(NODE root)
{
    if (root != NULL)
    {
        printf("%d ", root->data);
        preorder(root->lchild);
        preorder(root->rchild);
    }
}
void postorder(NODE root)
{
    if (root != NULL)
    {
        postorder(root->lchild);
        postorder(root->rchild);
        printf("%d ", root->data);
    }
}
void main()
{
    int ch, key, val, i, n, elem;
    NODE root = NULL, newnode;
    // clrscr();
    while (1)
    {
        printf("\n~~~~BST MENU~~~~");
        printf("\n1.Create a BST");
        printf("\n2.Search");
        printf("\n3.BST Traversals: ");
        printf("\n4.Exit");
        printf("\nEnter your choice: ");
        scanf("%d", &ch);
        switch (ch)
        {
        case 1:
            printf("\nEnter the number of elements: ");
            scanf("%d", &n);
            for (i = 1; i <= n; i++)
            {
                newnode = get_node();
                printf("\nEnter The value: ");
                scanf("%d", &val);
                newnode->data = val;

                if (root == NULL)
                    root = newnode;
                else
                    insert(root, newnode);
            }
            break;
        case 2:
            printf("\nEnter Element to be searched: ");
            scanf("%d", &key);
            search(root, key);
            break;
        case 3:
            if (root == NULL)
                printf("\nTree Is Not Created");
            else
            {
                printf("\nThe Preorder display : ");
                preorder(root);
                printf("\nThe Inorder display : ");
                inorder(root);
                printf("\nThe Postorder display : ");
                postorder(root);
            }
            break;
        case 4:
            exit(0);
        }
    }
}