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Program for find the preorder , postorder and inorder traversal of the binary search tree.

Rajnish Tripathi 22:19

 What is binary search tree:-

                                                Binary search tree is a node based binary tree data structure which has following properties:-



  • The left subtree of a node contains only nodes which has the less value.
  • The right subtree of a node contains only nodes which has the greater value .
  • The left and right subtree each must also be a binary search tree.


  • Tree traversal of the binary search tree:-


  •   (a) Inorder (Left, Root, Right) : 4 2 5 1 3
    (b) Preorder (Root, Left, Right) : 1 2 4 5 3
    (c) Postorder (Left, Right, Root) : 4 5 2 3 1
  • Solution:-
  • #include<stdio.h>
    #include<stdlib.h>
    struct binary_s_tree
    {
    int data;
    struct binary_s_tree *left;
    struct binary_s_tree *right;
    };
    struct binary_s_tree *root=NULL;

    // function for create createnode

    struct binary_s_tree *createnode()
    {
    struct binary_s_tree *n;
    n=(struct binary_s_tree*)malloc(sizeof(struct binary_s_tree));
    return n;
    }

    // function insert element into tree

    void insert()
    {
    struct binary_s_tree *temp,*n;
    n=createnode();
    printf("Enter value\n");
    scanf("%d",&n->data);
    n->left=NULL;
    n->right=NULL;
    if(root==NULL)
    root=n;
    else
    {
    temp=root;
    while(temp!=NULL)
    {
    if(temp->data>n->data)
    {
    if(temp->left==NULL)
    {
    temp->left=n;
    temp=temp->left;
    }
    temp=temp->left;
    }
    else
    {
    if(temp->right==NULL)
    {
    temp->right=n;
    temp=temp->right;
    }
    temp=temp->right;
    }
    }
    }
    }

    // function for preorder traversal

    void preorder_traversal(struct binary_s_tree *temp)
    {
    if(temp)
    {
    printf("%d ",temp->data);
    preorder_traversal(temp->left);
    preorder_traversal(temp->right);
    }
    }

    // function for post order traversal

    void postorder_traversal(struct binary_s_tree *temp)
    {
    if(temp)
    {
    postorder_traversal(temp->left);
    postorder_traversal(temp->right);
    printf("%d ",temp->data);
    }
    }

    // function for inorder traversal

    void inorder_traversal(struct binary_s_tree *temp)
    {
    if(temp)
    {
    inorder_traversal(temp->left);
    printf("%d ",temp->data);
    inorder_traversal(temp->right);
    }
    }
    int main()
    {
    int ch;
    printf("1. insert element into tree\n");
    printf("2. preorder traversal\n");
    printf("3. postorder traversal\n");
    printf("4. inorder traversal\n");
    printf("5. exit\n");
    while(1)
    {
    printf("\nEnter your choice\n");
    scanf("%d",&ch);
    switch(ch)
    {
    case 1: insert();
    break;
    case 2: preorder_traversal(root);
    break;
    case 3: postorder_traversal(root);
    break;
    case 4: inorder_traversal(root);
    break;
    case 5: exit(0);
    default: printf("Wrong key\n");
    }
    }
    return 0;
    }




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