/**
 ******************************************************************************
 * file name : bt_driver.cpp
 * author    : Hung Q. Ngo
 * description: test some tree traversal routines
 ******************************************************************************
 */
#include <iostream>
#include <sstream>
#include <cstdlib>  // for rand() and srand()
#include <ctime>    // for time()
#include "BTree.h"

using namespace std;

// return random tree with n nodes
BTNode<string>* random_tree(size_t n);

/*
 * -----------------------------------------------------------------------------
 * main body: test various functions
 * -----------------------------------------------------------------------------
 */
int main() {
    // first, test it with a simple expression tree 2*(4+3)-6
    // the following reminds me a lot of scheme/lisp
    BTNode<string>* tree =
        new BTNode<string>(
            "-", 
            new BTNode<string>(
                "*",
                new BTNode<string>("2"),
                new BTNode<string>(
                    "+", 
                    new BTNode<string>("4"), 
                    new BTNode<string>("3")
                    ) 
                ),
            new BTNode<string>("6")
        );

    levelorder_print(tree); cout << endl;

    inorder_print(tree);    cout << endl;
    preorder_print(tree);   cout << endl;
    postorder_print(tree);  cout << endl;

    clear_tree(tree);

    // traverse + print a random tree for fun
    srand(static_cast<unsigned int>(time(0)));
    tree = random_tree(10);

    inorder_print(tree); cout << endl;
    postorder_print(tree); cout << endl;
    preorder_print(tree); cout << endl;

    clear_tree(tree);
    return 0;
}

/*
 * -----------------------------------------------------------------------------
 * create a random binary tree with n nodes and return a pointer to the root
 * -----------------------------------------------------------------------------
 */
BTNode<string>* random_tree(size_t n) {
    ostringstream oss;
    oss << (rand() % 100);
    switch (n) {
    case 0:
        return NULL;
    case 1:
        return new BTNode<string>(oss.str());
    default:
        size_t k = rand() % n;
        return new BTNode<string>(oss.str(), random_tree(k),
                                  random_tree(n-1-k));
    }
}