数据结构之---C语言实现二叉排序树（BinarySortTree）

这里又叫做二叉搜索树

代码：

//二叉排序树(二叉搜索树Binary Search Tree)
//杨鑫
#include <stdio.h>
#include <stdlib.h>
typedef struct node
{
	int key;
	struct node *lchild, *rchild;
}BSTNode, *BSTree;

//插入
int InsertBST(BSTree *bst, int k)
{
	BSTree r, s, pre;
	r = (BSTree)malloc(sizeof(BSTNode));
	r->key = k;
	r->lchild = NULL;
	r->rchild = NULL;
	if(*bst == NULL)
	{
		*bst = r;
		return 1;
	}
	pre = NULL;
	s = *bst;
	while(s)
	{
		if(k == s->key)
				return 0;
		else if(k < s->key)
		{
			pre = s;
			s = s->lchild;
		}
		else
		{
			pre = s;
			s = s->rchild;
		}
	}
	if(k < pre->key)
			pre->lchild = r;
	else
			pre->rchild = r;
	return 1;
}	


void CreateBST(BSTree *bst)
{
	int key;
	*bst = NULL;
	scanf("%d", &key);
	while(key != -1)
	{
		InsertBST(bst, key);
		scanf("%d", &key);
	}
}

/*
 *打印二叉树：
 *中序遍历
 * */
void InOrder(BSTree root)
{
	if(root != NULL)
	{
		InOrder(root->lchild);
		printf(" %d ", root->key);
		InOrder(root->rchild);
	}
}

/*
 *搜索
 * */
BSTree SearchBST(BSTree bst, int key)
{
	BSTree q;
	q = bst;
	//递归
	while(q)
	{
			if(q->key == key)
					return q;
			if(q->key > key)
					q=q->lchild;
			else
					q=q->rchild;
	}
	return NULL;                        //查找失败
}

int main()
{
	BSTree T;
	int tag = 1;
	int m, n;
	printf("建立二叉排序树，请输入序列以-1结束：\n");
	CreateBST(&T);
	printf("中序遍历二叉树，序列为：\n");
	InOrder(T);
	printf("\n");
	while(tag != 0)
	{
		printf("请输入你要查找的元素:\n");
		scanf("%d", &n);
		if(SearchBST(T, n) == NULL)
				printf("抱歉查找失败!\n");
		else
				printf("查找成功！查找的数字为%d\n", SearchBST(T,n)->key);
		printf("是否继续查找 是 ：请按 1 否则按 0:\n");
		scanf("%d", &tag);
	}
	return 0;
}

结果：