This C Program finds sum of all nodes in a binary tree.

Here is source code of the C Program to find the sum of all nodes in a binary tree. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

`/*`

`* C Program to Find the Sum of All Nodes in a Binary Tree`

`* 50`

`* /\`

`* 20 30`

`* /\`

`* 70 80`

`* /\ \`

`* 10 40 60`

`*/`

`#include <stdio.h>`

`#include <malloc.h>`

`/* Structure to create the binary tree */`

`struct btnode`

`{`

int value;

struct btnode *l;

struct btnode *r;

};

struct btnode *root = NULL;

int sum;

`/* Function Prototypes */`

void in_order_traversal(struct btnode *);

void in_order_sum(struct btnode *);

struct btnode *newnode(int);

void main()

`{`

`/* Inserting elements in the binary tree */`

root = newnode(50);

root->l = newnode(20);

root->r = newnode(30);

root->l->l = newnode(70);

root->l->r = newnode(80);

root->l->l->l = newnode(10);

root->l->l->r = newnode(40);

root->l->r->r = newnode(60);

printf("The elements of Binary tree are:");

in_order_traversal(root);

in_order_sum(root);

printf("\nThe sum of all the elements are:%d", sum);

`}`

`/* Code to dynamically create new nodes */`

struct btnode* newnode(int value)

`{`

struct btnode *temp = (struct btnode *)malloc(sizeof(struct btnode));

temp->value = value;

temp->l = NULL;

temp->r = NULL;

return temp;

`}`

`/* Code to display the elements of the binary tree */`

void in_order_traversal(struct btnode *p)

`{`

if (!p)

`{`

return;

`}`

in_order_traversal(p->l);

printf("%d->", p->value);

in_order_traversal(p->r);

`}`

`/* Code to find the sum of all elements in the tree */`

void in_order_sum(struct btnode *p)

`{`

if (!p)

`{`

return;

`}`

in_order_sum(p->l);

sum = sum + p->value;

in_order_sum(p->r);

`}`

$ cc tree15.c $ a.out The elements of Binary tree are:10->70->40->20->80->60->50->30 The sum of all the elements are:360

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