Tree Traversal

main.c

#include <stdio.h>
#include <malloc.h>
#define R return
struct node { int data; struct node* left; struct node* right; };

struct node* insert(struct node* tree, int val)
{
	if (tree == NULL) {
		tree = (struct node*) malloc(sizeof(struct node));
		tree->left = NULL;
		tree->right = NULL;
		tree->data = val;
	} else {
		if (val < tree->data) {
			printf("INSIDE L\n");
			tree->left = insert(tree->left, val);
		} else {
			printf("INSIDE R\n");
			tree->right = insert(tree->right, val);
		}
	}
	R tree;
}

struct node* create(struct node* tree)
{
	int val;
	printf("Enter value to insert: ");
	scanf("%d", &val);
	while (val != -1) {
		tree = insert(tree, val);
		printf("Enter value to be inserted: ");
		scanf("%d", &val);
	}
	R tree;
}

void inOrder(struct node* tree)
{
	if (tree == NULL) {
		R;
	} else {
		inOrder(tree->left);
		printf("%d\n", tree->data);
		inOrder(tree->right);
	}
}

void preOrder(struct node* tree)
{
	if (tree == NULL) {
		R;
	} else {
		printf("%d\n", tree->data);
		preOrder(tree->left);
		preOrder(tree->right);
	}
}

void postOrder(struct node* tree)
{
	if (tree == NULL) {
		R;
	} else {
		postOrder(tree->left);
		postOrder(tree->right);
		printf("%d\n", tree->data);
	}
}

int main() {
	struct node* tree;
	tree = create(tree);
	inOrder(tree);
	printf("\n");
	preOrder(tree);
	printf("\n");
	postOrder(tree);
	R 0;
}