Program to Add (Insert) a Node in BST
#include <iostream>
using namespace std;
struct Node {
int data;
Node *left, *right;
//Stores the address of the left child and right child
};
Node* createNode(int value) //Creates a function to make a new node.
{
Node* newNode = new Node();// Allocates memory for a new node
newNode->data = value;//Stores the given value.
newNode->left = NULL;//Initially, the left child is empty.
newNode->right = NULL;//Initially, the right child is empty.
return newNode;//Returns the address of the new node
}
Node* add(Node* root, int value) {
if (root == NULL) {
return createNode(value);
}
Node* – The function returns the address of a node.
add – Function name.
Node* root – Receives the address of the root node.
int value – Receives the value that we want to insert.
It checks whether the current node is empty or not.
If root == NULL, it means there is no node at that position.
So, we can insert a new node there.
if (value < root->data) {
root->left = add(root->left, value);
}
else if (value > root->data) {
root->right = add(root->right, value);
}
return root;
}
void inorder(Node* root) {
if (root != NULL) {
inorder(root->left);
cout << root->data << " ";
inorder(root->right);
}
}
It checks whether the current node exists or not.
If root is not NULL, execute the statements inside.
If root is NULL, stop that function call.
Inorder = Left → Root → Right
int main() {
Node* root = NULL;
root = add(root, 50);
root = add(root, 30);
root = add(root, 70);
root = add(root, 20);
root = add(root, 40);
cout << "BST after insertion: ";
inorder(root);
return 0;
}
