Program 17 - Binary Search Tree

	#include <stdio.h>
	#include <stdlib.h>
	struct node {
	int data;
	struct node *left, *right;
	};
	struct node *create(struct node *root, int num) {
	if(root == NULL){
	root = (struct node *) malloc(sizeof(struct node));
	root -> data = num;
	root -> left = root -> right = NULL;
	} else {
	if(num <= root -> data){
	root -> left = create(root -> left, num);
	} else {
	root -> right = create(root -> right, num);
	}
	}
	return root;
	}
	void inorder(struct node *root) {
	if(root != NULL) {
	inorder(root -> left);
	printf("%d ", root -> data);
	inorder(root -> right);
	}
	}
	void preorder(struct node *root) {
	if(root != NULL) {
	printf("%d ", root -> data);
	preorder(root -> left);
	preorder(root -> right);
	}
	}
	void postorder(struct node *root) {
	if(root != NULL) {
	postorder(root -> left);
	postorder(root -> right);
	printf("%d ", root -> data);
	}
	}
	int main() {
	struct node *root = NULL;
	int num;
	printf("***Create Binary Search Tree***\n");
	printf("Enter data: ");
	scanf("%d", &num);
	while(num != -1) {
	root = create(root, num);
	printf("Enter data or enter -1 to stop: ");
	scanf("%d", &num);
	}
	printf("Inorder: ");
	inorder(root);
	printf("\nPreorder: ");
	preorder(root);
	printf("\nPostorder: ");
	postorder(root);
	}