# C program to implement depth-first binary tree search using recursion

In this tutorial, we will learn how to implement depth-first binary tree search using recursion in C language? By Nidhi Last updated : August 10, 2023

## Problem statement

Create a binary tree and implement a depth-first binary search and print the nodes.

## C program to implement depth-first binary tree search using recursion

The source code to depth-first binary tree search using recursion is given below. The given program is compiled and executed using GCC compile on UBUNTU 18.04 OS successfully.

```// C program to implement depth-first binary tree search
// using recursion

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

typedef struct node {
int item;
struct node* left;
struct node* right;

} Node;

{
Node* temp = *root;
Node* prev = *root;

if (*root == NULL) {
*root = (Node*)malloc(sizeof(Node));

(*root)->item = item;
(*root)->left = (*root)->right = NULL;
}
else {
while (temp != NULL) {
if (item > temp->item) {
prev = temp;
temp = temp->right;
}
else {
prev = temp;
temp = temp->left;
}
}
temp = (Node*)malloc(sizeof(Node));
temp->item = item;

if (item >= prev->item)
prev->right = temp;
else
prev->left = temp;
}
}

void DFS(Node* root)
{
if (root) {
if (root->left)
DFS(root->left);

if (root->right)
DFS(root->right);

printf("%d  ", root->item);
}
}

int main()
{

printf("\n");

return 0;
}
```

## Output

```30  60  40  20  10
```

## Explanation

Here, we created a self-referential structure to implement a Binary Tree, a function to add a node into the binary tree, and a recursive function DFS() to implement depth-first search and print the nodes.

In the main() function, we created a binary search tree, and called the function DFS() to print the nodes.