数据结构——递归实现二叉树

构造二叉树

typedef struct treenode
{
	TREE_TYPE data;
	struct treenode* left;/*指向左孩子*/
	struct treenode* right;/*指向右孩子*/

}Tree;

全部代码

#include<stdio.h>
#include<malloc.h>
typedef char TREE_TYPE;
typedef struct treenode
{
	TREE_TYPE data;
	struct treenode* left;/*指向左孩子*/
	struct treenode* right;/*指向左孩子*/

}Tree;
Tree* Create_Tree(Tree*&root)
{
	char ch;
	scanf_s("%c", &ch);
	if (ch == '#')/*出口*/
		root = NULL;
	else
	{
		root = (Tree*)malloc(sizeof(Tree));
		root->data = ch;
		root->left = Create_Tree(root->left);/*先创建左子树*/
		root->right = Create_Tree(root->right);/*在创建右子树*/

	}
	return root;

}
void Pre_order(Tree*&root)
{
	if (root)/*当root 指针不为空时*/
	{
		printf("%c\t", root->data);
		Pre_order(root->left);
		Pre_order(root->right);

	}


}
void Middle_order(Tree*&root)
{
	if (root)
	{
	    	Middle_order(root->left);
			printf("%c\t", root->data);
			Middle_order(root->right);
	}
}
void Back_order(Tree*& root)
{
	if (root)
	{
		Back_order(root->left);
		Back_order(root->right);
		printf("%c\t", root->data);
	}
}
int main(void)
{
	Tree* root = NULL;
	puts("Enter the node:");
	 Create_Tree(root);
	puts("The first order traversal:");
	Pre_order(root);
	puts("\nThe Middle order tracersal:");
	Middle_order(root);
	puts("\nThe back order is:");
	Back_order(root);

}