Sum of All Nodes In Binary Tree In C

March 20, 2025

Sum of all nodes in Binary Tree

Here, in this page we will write a C program to find the sum of all nodes in the given binary tree.

First, we will traverse through the left sub-tree and calculate the sum of nodes present in the left sub-tree. Similarly, we calculate the sum of nodes present in the right sub-tree and calculate total sum by adding the root’s data.

sum of all nodes

Sum of All Nodes In Binary Tree

Algorithm :

  • Create a function say, calculateSum() that will calculate the sum of nodes present in the binary tree.
  • It checks whether the root is null, which means that the tree is empty.
  • If the tree is not empty, traverse through left subtree, calculate the sum of nodes and store it in variable say, sumLeft.
  • Then, traverse through the right subtree, calculate the sum of nodes and store it in variable say, sumRight.
  • Finally, calculate total sum = root->data + sumLeft + sumRight.
Sum of All Nodes in Binary Tree in C-1

Check whether two tree are identical

Spiral Order traversal of Tree

Check If binary tree if Foldable or not

Check for Children-Sum in Binary Tree

Lowest Common Ancestor in Binary Tree

Code in C based on above approach

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

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

struct node *root = NULL;

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

int calculateSum (struct node *temp)
{
  int sum, sumLeft, sumRight;
  sum = sumRight = sumLeft = 0;

  if (root == NULL)
    {
      printf ("Tree is empty\n");
      return 0;
    }
  else
    {
      if (temp->left != NULL)
	sumLeft = calculateSum (temp->left);
      if (temp->right != NULL)
	sumRight = calculateSum (temp->right);

      sum = temp->data + sumLeft + sumRight;
      return sum;
    }
}

int main ()
{
  root = createNode (10);
  root->left = createNode (20);
  root->right = createNode (30);
  root->left->left = createNode (40);
  root->right->left = createNode (50);
  root->right->right = createNode (60);

  printf ("Sum of all nodes of binary tree: %d", calculateSum (root));
  return 0;
}

Output:

Sum of all nodes of binary tree: 210