順序二叉樹實現

#include"stdio.h"  
#include"stdlib.h"  
#include"iostream"

typedef struct bstnode{
    int data;
    struct bstnode *lchild;
    struct bstnode *rchild;
}bstnode, *BSTree; //結構體類型,BSTree為結構體指針

//函數聲明區
BSTree create_BSTree(int *arr, int len);
BSTree search(BSTree pTree, int key);
void in_traverse(BSTree pTree);
bool search_BSTree(BSTree pTree, int key, BSTree parent, BSTree &p);
bool insert(BSTree &pTree, int key);

//根據所給的長為len的arr數組，按數組中元素的順序構建一棵二叉排序樹
BSTree create_BSTree(int *arr, int len) {
    BSTree pTree = NULL;  //初始化樹為空樹
    int i;
    for (i = 0; i<len; i++)
        insert(pTree, arr[i]);  //
    return pTree;   //將數組中的數插入后返回
}

void in_traverse(BSTree pTree) {
    if (pTree){      //如果樹不為空則中序遞歸的打印出樹中的元素
        if (pTree->lchild)
            in_traverse(pTree->lchild);
        printf("%d ", pTree->data);
        if (pTree->rchild)
            in_traverse(pTree->rchild);
    }
}

BSTree search(BSTree pTree, int key){
    if (!pTree || pTree->data == key)   //如果樹不為空，
        return pTree;
    else if (key < pTree->data)        //如果key的值小於data,則往左搜索，否則往右，遞歸的進行
        return search(pTree->lchild, key);
    else                              
        return search(pTree->rchild, key);
}

bool search_BSTree(BSTree pTree, int key, BSTree parent, BSTree &p){     //用於查找到inset函數要用到的待插入元素位置的指針
    if (!pTree){     //如果樹中沒有元素，直接返回根節點
        p = parent;
        return false;
    }
    else {
        if (key == pTree->data){
            p = pTree;   //p保存訪問的最后一個結點指針
            return true;
        }
        else if (key < pTree->data)
            return search_BSTree(pTree->lchild, key, pTree, p);
        else                       
            return search_BSTree(pTree->rchild, key, pTree, p);
    }
}

bool insert(BSTree &pTree, int key){
    BSTree p;
    if (!search_BSTree(pTree, key, NULL, p)){
        BSTree pNew = (BSTree)malloc(sizeof(bstnode));
        pNew->data = key;
        pNew->lchild = pNew->rchild = NULL;   //分配一個新節點
        if (!p)                        
            pTree = pNew;
        else if (key < p->data)         
            p->lchild = pNew;          
        else
            p->rchild = pNew;
    }
    else
        return false;
}
void delete_bstnode1(BSTree &p){
    BSTree q, s;
    if (!p->lchild){  
        q = p;
        p = p->rchild;
        free(q);
    }
    else if (!p->rchild){  
        q = p;
        p = p->lchild;
        free(q);
    }
    else{     
        s = p->lchild;      
        while (s->rchild)
            s = s->rchild;
        s->rchild = p->rchild;  
        q = p;
        p = p->lchild;    
        free(q);
    }
}

bool delete_BSTree(BSTree &pTree, int key){
    if (!pTree)
        return false;
    else{
        if (key == pTree->data){
            delete_bstnode1(pTree);
            return true;
        }
        else if (key < pTree->data)  
            return delete_BSTree(pTree->lchild, key);
        else                       
            return delete_BSTree(pTree->rchild, key);
    }
}

void main(){
    int i;
    int num;
    printf("請輸入節點個數：");
    scanf_s("%d", &num);
    int *arr = (int *)malloc(num * sizeof(int));
    printf("請依次輸入這%d個整數（必須互不相等）：", num);
    for (i = 0; i<num; i++)
        scanf_s("%d", arr + i);
    BSTree pTree = create_BSTree(arr, num);
    printf("中序遍歷該二叉排序樹的結果：");
    in_traverse(pTree);
    printf("\n");
    int key;
    printf("請輸入要查找的整數：");
    scanf_s("%d", &key);
    if (search(pTree, key))
        printf("查找成功，%d存在\n",key);
    else
        printf("查找不到該整數\n");
    printf("請輸入要插入的整數：");
    scanf_s("%d", &key);
    if (insert(pTree, key)){
        printf("插入成功，插入后的中序遍歷結果：");
        in_traverse(pTree);
        printf("\n");
    }
    else
        printf("插入失敗，該二叉排序樹中已經存在整數%d\n", key); 
    printf("請輸入要刪除的整數：");
    scanf_s("%d", &key);
    if (delete_BSTree(pTree, key)){
        printf("刪除成功，插入后的中序遍歷結果：");
        in_traverse(pTree);
        printf("\n");
    }
    else
        printf("刪除失敗，該二叉排序樹中不存在整數%d\n", key);
    system("pause");
}