Find Size of Binary Tree in C

March 19, 2025

Size of Binary Tree

 

Size of Binary tree is defined as the number of nodes in the given tree. It can be easily calculated using recursion and tree traversals. In this article this problem is solved using recursion.

size of binary tree

Find Size of Binary Tree In C

Algorithm :

  • If node is empty, return NULL.
  • Otherwise, recursively call the size function for the left and right subtree.
  • Return 1 + sum of left and right subtree.
Find Size of Binary Tree in C

Construct Tree from given Postorder and Preorder traversal 

Find the height of binary tree

Check whether two tree are identical

Spiral Order traversal of Tree

Check If binary tree if Foldable or not

Code For Find The Size of Binary Tree In C

Run 
#include <stdio.h>
#include <stdlib.h>

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

struct node *newNode (int data)
{
  struct node *node = (struct node *) malloc (sizeof (struct node));
  node->data = data;
  node->left = NULL;
  node->right = NULL;

  return (node);
}

int size (struct node *node)
{
  if (node == NULL)
    return 0;
  else
    return (size (node->left) + 1 + size (node->right));
}

int main ()
{
  struct node *root = newNode (10);
  root->left = newNode (20);
  root->right = newNode (30);
  root->left->left = newNode (40);
  root->left->right = newNode (50);

  printf ("Size of the tree is %d", size (root));
  getchar ();
  return 0;
}

Output:

Size of the tree is 5