Question

**Bonus Question** Write a C function with signature bt' bstree (int' post, int size) that gets the post-order traversal of a binary search tree in the form of an int array, reconstructs the tree and returns a pointer to the tree root as output (The second input parameter size specifies the number of elements in the tree). Note: Type bt is defined in the following way: typedef struct btreenode { struct btreenode *left; int data; struct btreenode "right; bt;

Answer 1

Did not follow the convention mentioned in the note,change/amend code according to your own volition

#include <stdio.h>

#include <stdlib.h>

/* A binary tree node has data, pointer to left child

   and a pointer to right child */

struct node

{

     int data;

     struct node* left;

     struct node* right;

};

/* Helper function that allocates a new node with the

   given data and NULL left and right pointers. */

struct node* newNode(int data)

{

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

     node->data = data;

     node->left = NULL;

     node->right = NULL;

     return(node);

}

/* post order */

void printPostorder(struct node* node)

{

     if (node == NULL)

        return;

     printPostorder(node->left);

     printPostorder(node->right);

     printf("%d ", node->data);

}

int main()

{

     struct node *root = newNode(1);

     root->left             = newNode(2);

     root->right           = newNode(3);

     root->left->left     = newNode(4);

     root->left->right   = newNode(5);

printf("\nPostorder traversal of binary tree is \n");

     printPostorder(root);

getchar();

     return 0;

}