How to insert a node in Binary Search Tree?

Binary Search Tree is very important data structure in computer science. I am trying to cover most of it in the article. You should be able to answer following questions after reading (and understanding) the article.

• What is Binary Search Tree?
• Why Binary Search Tree is used for?
• How to insert a node in a Binary Search Tree?

A  Binary search tree (BST) or ordered binary tree is a node-based binary tree data structure which has the following properties:

• The left subtree of a node contains only nodes with keys less than the node’s key.
• The right subtree of a node contains only nodes with keys greater than the node’s key.

Both the left and right subtrees must also be binary search trees.

Generally, the information represented by each node is a record rather than a single data element. However, for sequencing purposes, nodes are compared according to their keys rather than any part of their associated records.

The major advantage of binary search trees over other data structures is that the related sorting algorithms and search algorithms such as in-order traversal can be very efficient.

Binary search trees are a fundamental data structure used to construct more abstract data structures such as sets, multisets, and associative arrays.

Structure of Binary Search Tree Node:

struct tnode {
int data;
struct tnode *left;
struct tnode *right;
};

Data is an integer, which will contain the actual data and left and right are again the Binary Search Tree nodes containing left and right subtrees.

How to insert a Node in Binary Search Tree:

While inserting a new node to binary search tree, we need to maintain the basic property of Binary Search Tree . Traverse through the tree and find out the correct position for the given node.

struct tnode *insert(struct tnode *p , int val){
        if(p==NULL){
                p = (struct tnode *)malloc(sizeof(struct tnode));
                p->data = val;
                p->left = NULL;
                p->right = NULL;
        }else{
                struct tnode *q,*temp;
                q=p;
                temp=p;
                while(q != NULL ){
                        temp= q;
                        if( val >= temp->data)
                                q=temp->right;
                        else
                                q=temp->left;
                }
                struct tnode *n;
                n= (struct tnode *)malloc (sizeof(struct tnode));
                n->data =val;
                if( val >=temp->data )
                        temp->right =n;
                else
                        temp->left = n;
        }
        return p;
}