Tree Example

Example : A simple program in C to create a Binary Tree up to 3 levels.

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

// Define structure of a tree node
struct Node 
{
    int data;
    struct Node* left;
    struct Node* right;
};

// Function to create a new node
struct Node* createNode(int value) 
{
    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
    newNode->data = value;
    newNode->left = NULL;
    newNode->right = NULL;
    return newNode;
}

int main() 
{
    int val;

    // Create root node
    printf("Enter value for root: ");
    scanf("%d", &val);
    struct Node* root = createNode(val);

    // Level 2 (children of root)
    printf("Enter value for left child of %d: ", root->data);
    scanf("%d", &val);
    root->left = createNode(val);

    printf("Enter value for right child of %d: ", root->data);
    scanf("%d", &val);
    root->right = createNode(val);

    // Level 3 (children of left child)
    printf("Enter value for left child of %d: ", root->left->data);
    scanf("%d", &val);
    root->left->left = createNode(val);

    printf("Enter value for right child of %d: ", root->left->data);
    scanf("%d", &val);
    root->left->right = createNode(val);

    // Level 3 (children of right child)
    printf("Enter value for left child of %d: ", root->right->data);
    scanf("%d", &val);
    root->right->left = createNode(val);

    printf("Enter value for right child of %d: ", root->right->data);
    scanf("%d", &val);
    root->right->right = createNode(val);

    // Display the tree in simple form
    printf("\nBinary Tree (3 Levels):\n");
    printf("        %d\n", root->data);
    printf("       /  \\\n");
    printf("     %d   %d\n", root->left->data, root->right->data);
    printf("    / \\   / \\\n");
    printf("   %d %d %d  %d\n",
           root->left->left->data,
           root->left->right->data,
           root->right->left->data,
           root->right->right->data);

    return 0;
}

Output:
Enter value for root: 400
Enter value for left child of 400: 10
Enter value for right child of 400: 20
Enter value for left child of 10: 30
Enter value for right child of 10: 40
Enter value for left child of 20: 50
Enter value for right child of 20: 20

Binary Tree (3 Levels):
        400
       /  \
     10   20
    / \   / \
   30 40 50  20