《实验六》

#include 
#include 
typedef int ElemType;
typedef struct node
{
    ElemType data;                 
    struct node *lchild;
	struct node *rchild;
} node, *BTree;
void Insert(BTree *T, ElemType x)
{
    BTree p, m, s;
    m = p = NULL;
    if (!Search(*T, x, &p, &m)) {
        s = (node *)malloc(sizeof(node));
        s->data = x;
        s->lchild = NULL;
        s->rchild = NULL;
        if (!*T)
            *T = s;
        else
		{
            if (x < m->data)
                m->lchild = s;
            else
                m->rchild = s;
        }
    }
}
void Create(BTree *T)
{
    ElemType x;
    printf("请输入若干整数构建BST，以 -1 结束：n");
    *T = NULL;
    scanf("%d", &x);
    while (x != -1) {
        Insert(T, x);
        scanf("%d", &x);
    }
}
void Delete(BTree *T, ElemType x)
{
    BTree p, f, s, s_parent;
    p = f = NULL;
    if (Search(*T, x, &p, &f)) {
        if (!p->lchild && !p->rchild) {
            if (p == *T) {
                *T = NULL;
                free(p);
            }
            else {
                if (p->data < f->data)
                    f->lchild = NULL;
                else
                    f->rchild = NULL;
                free(p);
            }
        }
        else if (!p->lchild && p->rchild) {
            if (p == *T) {
                *T = p->rchild;
                free(p);
            }
            else {
                if (p->data < f->data)
                    f->lchild = p->rchild;
                else
                    f->rchild = p->rchild;
                free(p);
            }
        }
        else if (p->lchild && !p->rchild) {
            if (p == *T) {
                *T = p->lchild;
                free(p);
            }
            else {
                if (p->data < f->data)
                    f->lchild = p->lchild;
                else
                    f->rchild = p->lchild;
                free(p);
            }
        }
        else {
            s_parent = p;
            s = p->lchild;
            while (s->rchild)
            {
                s_parent = s;
                s = s->rchild;
            }
            p->data = s->data;
            if (s_parent == p)
                s_parent->lchild = s->lchild;
            else
                s_parent->rchild = s->lchild;
            free(s);
        }
    }
}
int Search(BTree T, ElemType x, BTree *p, BTree *f)
{
    *p = T;
    while (*p)
	{
        if ((*p)->data == x)
            return 1;
        else {
            if (x < (*p)->data) {
                *f = *p;
                *p = (*p)->lchild;
            }
            else {
                *f = *p;
                *p = (*p)->rchild;
            }
        }
    }
 
    return 0;
}
void Traverse(BTree T)
{
    if (T) {
        Traverse(T->lchild);
        printf("%d, ", T->data);
        Traverse(T->rchild);
    }
}

int main()
{
	int flag;
	int a,b,c;
	char t;
    BTree T, p, f;
    p = f = NULL;
    Create(&T);
    printf("遍历：");
    Traverse(T);
    printf("n");
    printf("请输入想要查找的数字(退出请输入-1)：");
	while(1)
	{
	   scanf("%d",&c);
      if(c==-1)
      {
          break; 
	  }
       flag = Search(T, c, &p, &f);
       if (flag)
           printf("success,the value is%dn",c);
       else
           printf("unsuccessn");
	}
    printf("输入想要插入的数字：");
	scanf("%d",&a);
    Insert(&T, a);
    Traverse(T);
    printf("n");
    printf("输入想要删除的数字:");
	scanf("%d",&b);
    Delete(&T, b);
    Traverse(T);
    printf("n");
 
    return 0;
}