查找树ADT--二叉查找树

/*Tree.h*/#ifndef _Tree_Hstruct TreeNode;typedef struct TreeNode *Position;typedef struct TreeNode *SearchTree;typedef int ElementType;SearchTree MakeEmpty(SearchTree T);Position Find(ElementType X, SearchTree T);Position FindMin(SearchTree T);Position FindMax(SearchTree T);SearchTree Insert(ElementType X, SearchTree T);SearchTree Delete(ElementType X, SearchTree T);ElementType Retrieve(Position P);#endif // !_Tree_H

/*Tree.cpp*/#include<stdio.h>#include<stdlib.h>#include"Tree.h"struct TreeNode{    ElementType Element;    SearchTree Left;    SearchTree Right;};SearchTree MakeEmpty(SearchTree T){    if (T != NULL)    {        MakeEmpty(T->Left);        MakeEmpty(T->Right);        free(T);    }    return NULL;}Position Find(ElementType X, SearchTree T){    if (T == NULL)        return NULL;    if (X < T->Element)        return Find(X, T->Left);    else if (X > T->Element)        return Find(X, T->Right);    else        return T;}Position FindMin(SearchTree T){    if (T == NULL)        return NULL;    else if (T->Left == NULL)        return T;    else        return FindMin(T->Left);}Position FindMax(SearchTree T){    if (T != NULL)        while (T->Right != NULL)            T = T->Right;    return T;}SearchTree Insert(ElementType X, SearchTree T){    if (T == NULL)    {        /*Creat and return a one-node tree*/        T = (TreeNode*)malloc(sizeof(struct TreeNode));        if (T = NULL)            printf("Out of space!");        else        {            T->Element = X;            T->Left = T->Right = NULL;        }    }    else if (X < T->Element)        T->Left = Insert(X, T->Left);    else if (X > T->Element)        T->Right = Insert(X, T->Right);    /*else X is in the tree already;we'll do nothing*/    return T;}SearchTree Delete(ElementType X, SearchTree T){    Position TmpCell;    if (T = NULL)        printf("Element not found!");    else if (X > T->Element)/*Go left*/        T->Left = Delete(X, T->Left);    else if (X < T->Element)/*Go right*/        T->Right = Delete(X, T->Right);    /*Found element to be deleted*/    else if (T->Left&&T->Right)/*Two children*/    {        /*Repalce with smallest in right subtree*/        TmpCell = FindMin(T->Right);        T->Element = TmpCell->Element;        T->Right = Delete(T->Element, T->Right);    }    else /*One or zero children*/    {        TmpCell = T;        if (T->Left = NULL)/*Aslo handles 0 child*/            T = T->Right;        else if (T->Right = NULL)            T = T->Left;        free(TmpCell);    }    return T;}int main(){    SearchTree T{} ;    Insert(1, T);    Insert(2, T);    Insert(3, T);    Insert(4, T);    Insert(5, T);    Insert(6, T);    Insert(8, T);    printf("%d", FindMin(T)->Element);    printf("%d", FindMax(T)->Element);    printf("%d", Find(4, T)->Element);    Delete(4, T);    Find(4, T);    MakeEmpty(T);    return 0;}