C语言数据结构，二叉树的基本操作。

#include<stdio.h>
#define ok 1
#define error 0
#define NULL 0

typedef int type_data;
typedef struct node {
	type_data data;
	struct node* left, * right;
}node;
//初始化一棵树
node* creat(node* tree) {
	//node *tree=new node;
	tree = NULL;
	return tree;

}
/* 按先序次序建立一个二叉树*/
node* BinTreeCreat(node *tree)
{
	//node *tree;
	int e;
	printf("请输入值，按0停止输入：");
	scanf_s("%d", &e);
	//return tree;
	if(e==0)
	{
		tree =NULL;
		//tree->left = NULL;
		//tree->right = NULL;
		return tree;
	}
	else {
		tree = new node;
		tree->data = e;
		//tree->left = NULL;
		//tree->right = NULL;
		BinTreeCreat(tree->left);
		BinTreeCreat(tree->right);
		

	}
	return tree;
	
}

/*node* BinTreeCreat(node* tree)
{
	node* w = new node;
	tree= w;
	int e;
	printf("请输入值，按0停止输入：");
	scanf_s("%d", &e);
	if (e == 0)
	{
		w= NULL;//不能让tree=NULL；因为要让《每次》改变后的值为空！
		return w;
	}
	if (w != NULL)
	{
		w->data = e;
		//w->left = NULL;
		//w->right = NULL;
		w->left=BinTreeCreat(w->left);
		w->right=BinTreeCreat(w->right);
	}

	return tree;

}*/

/* 检查二叉树是否为空 */
type_data BinTreeEmpty(node* tree)
{
	if (tree == NULL)
	{
		printf("该二叉树为空！");
		return ok;
	}
	else
	{
		printf("该二叉树不为空！");
		return error;
	}
}

/* 按任一种遍历次序（包括按先序、中序、后序、按层次）输出二叉树中的所有结点 */
/*type_data BinTraverse(node* tree,int x)
{
	
	if (!tree)
	{
		printf("该二叉树为空！");
		return error;
	}
	if (x == 1)
	{
		if (tree->data > -9999&& tree->data < 9999) {
			printf("该二叉树的先序遍历为：");
			printf("%2d", tree->data);
			BinTraverse(tree->left, x);
			BinTraverse(tree->right, x);
		}
	}
	else if (x == 2)
	{
		printf("该二叉树的中序遍历为：");
		if (tree->data > -9999 && tree->data < 9999) {
			BinTraverse(tree->left, x);
			printf("%2d", tree->data);
			BinTraverse(tree->right, x);
		}
	}
	else if (x== 3)
	{
		if (tree->data > -9999 && tree->data < 9999) {
			printf("该二叉树的后序遍历为：");
			BinTraverse(tree->left, x);
			BinTraverse(tree->right, x);
			printf("%2d", tree->data);
		}
	}
	else
	{
		printf("你输入的选项错误！请继续输入：\n");
		scanf_s("%d", &x);

	}
	return ok;


}*/
//遍历二叉树
type_data BinTraverse(node* tree,int x)
{

	if (tree==NULL)
	{
		//printf("该二叉树为空！");
		return NULL;
	}
	if (x == 1)
	{
		//if (tree->data > -9999&& tree->data < 9999) {
		//printf("该二叉树的先序遍历为：");
		printf("%2d", tree->data);
		BinTraverse(tree->left, x);
		BinTraverse(tree->right, x);
		//}
	}
	else if (x == 2)
	{
		//printf("该二叉树的中序遍历为：");
		//if (tree->data > -9999 && tree->data < 9999) {
		BinTraverse(tree->left, x);
		printf("%2d", tree->data);
		BinTraverse(tree->right, x);
		//}
	}
	else if (x== 3)
	{
		//if (tree->data > -9999 && tree->data < 9999) {
		//printf("该二叉树的后序遍历为：");
		BinTraverse(tree->left, x);
		BinTraverse(tree->right, x);
		printf("%2d", tree->data);
		//}
	}
	else
	{
		printf("你输入的选项错误！请继续输入：\n");
		scanf_s("%d", &x);

	}
	return ok;


}

/* 求二叉树的深度 */
type_data BinTreeDepth(node* tree)
{
	if (tree== NULL)
	{
		//printf("该二叉树为空！");
		return 0;
	}
	else
	{
		int hl=0, hr=0;
		//tree = tree->left;
		hl = BinTreeDepth(tree->left);
		//tree = tree->right;
		hr = BinTreeDepth(tree->right);
		if (hl > hr) {
			return hl+1;
			//printf("该二叉树的深度为：%d", hl + 1);
		}
		else
		{
			return hr+1;
			//printf("该二叉树的深度为：%d", hr + 1);
		}
	}
	//return ok;
}
/* 求二叉树中所有结点数 */
type_data BinTreeCount(node* tree)
{
	//int count = 0;
	if (tree == NULL)
	{

		//printf("该二叉树为空！");
		return 0;

	}
	else
	{

		return BinTreeCount(tree->left) + BinTreeCount(tree->right)+1;
		//return ;
	}

}
/* 清除二叉树，使之变为空树 */
void BinTreeClear(node* tree)
{
	tree = NULL;
	printf("该二叉树已销毁！");
}
void main()
{
	node *tree = new node;
	printf("1-初始化二叉树：\n");
	printf("2-检查二叉树栈是否为空\n");
	printf("3-清除二叉树\n");
	printf("4-遍历二叉树\n");
	printf("5-计算二叉树的深度\n");
	printf("6-计算二叉树的所有节点\n");
	printf("7-创建二叉树！\n");
	int y, r = 0, l = 0,x;
	//做一个do……while循环，确保在swtich……case语句里，每一项功能执行后都能继续执行总程序
	do {
		printf("请你选择功能！\n");
		int week;
		scanf_s("%d", &week);
		switch (week)
		{
		case 1:
			tree=creat(tree);
			printf("初始化成功！\n");
			printf("请选择是否执行功能：1or0\n");
			scanf_s("%d", &y);
			//用if语句判断，是否继续功能，下同
			if (y == 1)
			{

				continue;
			}
			else
				break;
		case 2:
			BinTreeEmpty(tree);
			printf("请选择是否执行功能：1or0\n");
			scanf_s("%d", &y);
			if (y == 1)
			{
				continue;
			}
			else
				break;
		case 3:
			BinTreeClear(tree);
			printf("请选择是否执行功能：1or0\n");
			scanf_s("%d", &y);
			if (y == 1)
			{
				continue;
			}
			else
				break;

		case 4:
			//int r;

			printf("请输入你要选择的遍历方法1or2or3：");
			scanf_s("%d", &x);
			BinTraverse(tree,x);
			printf("请选择是否执行功能：1or0\n");
			scanf_s("%d", &y);
			if (y == 1)
			{
				continue;
			}
			else
				break;
		case 5:
			BinTreeDepth(tree);
			printf("该二叉树的高度为：%d\n", BinTreeDepth(tree));
			printf("请选择是否执行功能：1or0\n");
			scanf_s("%d", &y);
			if (y == 1)
			{
				continue;
			}
			else
				break;


		case 6:
			BinTreeCount(tree);
			//get_top(s,l);
			printf("你的二叉树的结点数量为：%d\n", BinTreeCount(tree));
			printf("请选择是否执行功能：1or0\n");
			scanf_s("%d", &y);
			if (y == 1)
			{
				continue;
			}
			else
				break;
		case 7:
			tree=BinTreeCreat(tree);
			//get_top(s,l);
			//printf("你获得的栈顶元素为：%d\n", get_top(s, l));
			printf("请选择是否执行功能：1or0\n");
			scanf_s("%d", &y);
			if (y == 1)
			{
				continue;
			}
			else
				break;
		}

	} while (y == 1);
}