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

#define WORD_LENGTH 30

typedef struct tree_node
{
    char  *word;
    struct tree_node *left, *right;
} TreeNode;

void insert(TreeNode **root, char word[]);
TreeNode * searchNode(TreeNode *rt, char key[]);
void printTree(TreeNode *rt, int level);
void printInOrder(TreeNode *rt);
void printPreOrder(TreeNode *rt);


int main(int argc, char *argv[])
{
    TreeNode *root = NULL;  /* don't forget to initially NULL this ptr! */
    TreeNode *ptr;
    int count;
    char target[WORD_LENGTH];

    for (count = 1; count < argc; count++)
	insert(&root, argv[count]);

    printf("\nInorder traversal of tree:\n");
    printInOrder(root);

    printf("\nPreorder traversal of tree:\n");
    printPreOrder(root);

    printTree(root, -1);

    printf("Enter a word to search for ['q' to quit]: ");
    scanf("%s", target);
    while (target[0] != 'q')
    {
	if ((ptr = searchNode(root, target)) != NULL)
	    printf("  %s found in tree!\n", ptr->word);
	else
	    printf("  %s not found in tree!\n", target);
	printf("\nAnother word to search for ['q' to quit]: ");
	scanf("%s", target);
    }

    return 0;
}


void insert(TreeNode **root, char word[])
{
    if (*root == NULL)
    {
	*root = (TreeNode *)malloc(sizeof(TreeNode));
	(*root)->word = (char *)malloc(strlen(word)+1);
	strcpy((*root)->word, word);
	(*root)->left = (*root)->right = NULL;
    }
    else if (strcmp(word,(*root)->word) < 0)
	insert(&(*root)->left, word);
    else
	insert(&(*root)->right, word);
}


TreeNode * searchNode(TreeNode *rt, char key[])
{
    while (rt != NULL && strcmp(key, rt->word) != 0)
    {
	if (strcmp(key,rt->word) < 0)
	    rt = rt->left;
	else
	    rt = rt->right;
    }

    return rt;
}


void printInOrder(TreeNode *rt)
{
    if (rt != NULL)
    {
	printInOrder(rt->left);
	printf("%s\n",rt->word);
	printInOrder(rt->right);
    }
}


void printPreOrder(TreeNode *rt)
{
    if (rt != NULL)
    {
	printf("%s\n",rt->word);
	printPreOrder(rt->left);
	printPreOrder(rt->right);
    }
}


void printTree(TreeNode *rt, int level)
{
    int i;

    if (rt != NULL)
    {
	level++;
	printTree(rt->right, level);
	for(i = 0; i < level; i++)
	    printf("    ");
	printf("%s\n", rt->word);
	printTree(rt->left, level);
    }
}