排序二叉树

#include <iostream>
#include <stdlib.h>

using namespace std;

typedef int Elemtype;
struct TNode {
    Elemtype data;
    struct TNode *lChild, *rChild;
};
typedef struct Head {
    TNode *root;
} *Tree;

//函数声明
Tree init();
TNode * initNode();
void displayDESC(TNode *);
void add(Tree , Elemtype);
void displayASC(TNode *);

int main()
{
    Tree tree = init();
    int iSize;
    Elemtype insertValue;
    cout << "请输入要插入结点数：" << endl;
    cin >> iSize;
    for(int i = 0; i < iSize; i++) {
        cin >> insertValue;
        add(tree , insertValue);
    }
    cout << "排序后的树为(从小到大)：" << endl;
    displayDESC(tree->root);
    cout << endl;
    cout << "排序后的树为(从大到小)：" << endl;
    displayASC(tree->root);
    return 0;
}

//初始化一棵树
Tree init() {
    Tree t = (Tree)malloc(sizeof(Head));
    t->root = NULL;
    return t;
}

//初始化一个树结点
TNode * initNode() {
    TNode *t = (TNode *)malloc(sizeof(TNode));
    t->lChild = NULL;
    t->rChild = NULL;
    return t;
}

//从小到大展示树中所有元素
void displayDESC(TNode *root) {
    if(root == NULL) {
        return;
    }
    displayDESC(root->lChild);
    cout << root->data << " ";
    displayDESC(root->rChild);
}

//从大到小展示树中所有元素
void displayASC(TNode *root) {
    if(root == NULL) {
        return;
    }
    displayASC(root->rChild);
    cout << root->data << " ";
    displayASC(root->lChild);
}

//向树中添加元素结点
void add(Tree tree , Elemtype value) {
    //如果没有指向根结点的指针，直接返回
    if(tree == NULL) {
        return;
    }

    //初始化要插入的数据为一个树结点
    TNode *t = initNode();
    t->data = value;

    //如果没有根结点，把要插入的结点当作根结点插入
    if(tree->root == NULL) {
        tree->root = t;
        return;
    }

    //将要插入的点与树中的各结点值进行比较，小的放左树，大的放右树
    TNode *tCurr = tree->root;

    while(tCurr != NULL) {
        if(t->data <= tCurr->data) {
            if(tCurr->lChild != NULL) {
                tCurr = tCurr->lChild;
                continue;
            } else {
                tCurr->lChild = t;
                break;
            }
        } else {
            if(tCurr->rChild != NULL) {
                tCurr = tCurr->rChild;
                continue;
            } else {
                tCurr->rChild = t;
                break;
            }
        }
    }
}