Binary Tree Traversal Techniques (Inorder , Preorder , Postorder ) 🌟🌟🎊🎊👍👍

 By: Himanshu Tiwari

Algorithm Inorder(tree)

1 . Traverse the left subtree, i.e., call Inorder(left->subtree)

2 .Visit the root.

3 . Traverse the right subtree, i.e., call Inorder(right->subtree)

Algorithm Preorder(tree)

1 . Visit the root.

2 . Traverse the left subtree, i.e., call Preorder(left->subtree)

3 . Traverse the right subtree, i.e., call Preorder(right->subtree)

Algorithm Postorder(tree)

1 . Traverse the left subtree, i.e., call Postorder(left->subtree)

2 . Traverse the right subtree, i.e., call Postorder(right->subtree)

3 . Visit the root

#include <stdio.h>

#include <stdlib.h>

struct node {

  int data;

  struct node *left;

  struct node *right;

};

struct node *create_node(int data) {

  struct node *new_node = malloc(sizeof(struct node));

  new_node->data = data;

  new_node->left = NULL;

  new_node->right = NULL;

  return new_node;

}

void insert_node(struct node **root, int data) {

  if (*root == NULL) {

    *root = create_node(data);

    return;

  }

  if (data < (*root)->data) {

    insert_node(&(*root)->left, data);

  } else {

    insert_node(&(*root)->right, data);

  }

}

void print_tree(struct node * r) {

  if (r == NULL) {

    return;

  }

  print_tree(r->left);

  printf("%d ", r->data);

  print_tree(r->right);

}

void preorder(struct node * rr){

  if(rr!=NULL){

    printf("%d ",rr->data);

    preorder(rr->left);

    preorder(rr->right);

  }

}

void inorder(struct node * r){

  if(r!=NULL){

    inorder(r->left);

    printf("%d ",r->data);

    inorder(r->right);

  }

}

void postorder(struct node *r){

  if(r!=NULL){

    postorder(r->left);

    postorder(r->right);

    printf("%d ",r->data);

  }

}

int main() {

struct node *p=create_node(1);

struct node *p1=create_node(2);

struct node *p2=create_node(3);

struct node *p3=create_node(4);

struct node *p4=create_node(5);

struct node *p5=create_node(6);

struct node *p6=create_node(7);

p->left=p1;

p->right=p2;

p1->left=p3;

p1->right=p4;

p2->left=p5;

p2->right=p6;

  printf((" PREORDER  : "));

  preorder(p);

  printf("\n");

  printf(" INORDER   : ");

  inorder(p);

  printf("\n");

  printf(" POSTORDER : ");

  postorder(p);

  return 0;

}