建立一棵二叉排序樹

#include<stdio.h>
#include<stdlib.h>

typedef int ElemType;

typedef struct BTNode/*樹節點定義*/
{
	ElemType key;
	struct BTNode *lchild;
	struct BTNode *rchild;
}BTNode;

int BSTInsert(BTNode *&bt, int key)/*向二叉排序樹插入一個新的節點*/
{
	if (bt == NULL)/*找到了待插入元素的位置*/
	{
		bt = (BTNode*)malloc(sizeof(BTNode));
		bt->lchild = bt->rchild = NULL;
		bt->key = key;
		return 1;
	}
	else
	{
		if (key == bt->key)
			return 0;
		else if (key < bt->key)
			return BSTInsert(bt->lchild,key);
		else
			return BSTInsert(bt->rchild,key);
	}
}

void CreatBST(BTNode *&bt, int key[], int n)/*建立一個二叉排序樹*/
{
	int i;
	bt = NULL;
	for (i = 0; i < n; ++i)
		BSTInsert(bt,key[i]);
}

void inorder(BTNode *p)/*中序遍歷二叉樹*/
{
	if (p != NULL)
	{
		inorder(p->lchild);
		printf("%d ",p->key);
		inorder(p->rchild);
	}
}

int main()
{
	int i,k[10];
	printf("Please inter ten numbers:\n");
	for (i = 0; i < 10; ++i)
		scanf("%d",k+i);
	BTNode * bt;
	CreatBST(bt, k, 10);
	printf("After sort:\n");
	inorder(bt);
	return 0;
}