二叉树-----建立、先序遍历、中序遍历、后序遍历、求结点数、求度、求叶子结点数

#include<iostream>
using namespace std;

typedef struct BinaryTree
{
	int data;
	struct BinaryTree *Left;
	struct BinaryTree *Right;
}Node;


Node* createBinaryTree()
{
	Node *p = NULL;
	int c;
	while (cin >> c)
	{
		if (c == 0)     //叶子节点的左、右子树分别赋值为0
		{
			p = NULL;
		}
		else
		{
			p = (Node*)malloc(sizeof(Node));
			p->data = c;
			p->Left = createBinaryTree();  //递归创建左子树
			p->Right = createBinaryTree();  //递归创建右子树
		}
	}
	return p;
}



//先序遍历
void PreOrderTraverse(Node* BinaryRoot)
{
	if (BinaryRoot == NULL)
	{
		return;
	}
	cout << BinaryRoot->data << ' ';
	if(BinaryRoot->Left!=NULL)
		PreOrderTraverse(BinaryRoot->Left);
	if(BinaryRoot->Right!=NULL)
		PreOrderTraverse(BinaryRoot->Right);
}

//中序遍历
void InOrderTraverse(Node* BinaryRoot)
{
	if (BinaryRoot == NULL)
	{
		return;
	}
	if(BinaryRoot->Left!=NULL)	
		InOrderTraverse(BinaryRoot->Left);
	cout << BinaryRoot->data << ' ';
	if(BinaryRoot->Right!=NULL)	
		InOrderTraverse(BinaryRoot->Right);
}

//后序遍历
void LastOrderTraverse(Node* BinaryRoot)
{
	if (BinaryRoot == NULL)
		return;
	if(BinaryRoot->Left!=NULL)
		LastOrderTraverse(BinaryRoot->Left);
	if(BinaryRoot->Right!=NULL)	
		LastOrderTraverse(BinaryRoot->Right);
	cout << BinaryRoot->data << ' ';
}

//二叉树节点总数目
int NodeNum(Node* BinaryRoot)
{
	if (BinaryRoot == NULL)
	{
		return 0;
	}
	else
	{
		return 1 + NodeNum(BinaryRoot->Left) + NodeNum(BinaryRoot->Right);

	}
}

//二叉树的深度
int TreeDepth(Node* BinaryRoot)
{
	if (BinaryRoot)
	{
		return TreeDepth(BinaryRoot->Left) > TreeDepth(BinaryRoot->Right) ? TreeDepth(BinaryRoot->Left) + 1 : TreeDepth(BinaryRoot->Right) + 1;
	}
	if (BinaryRoot == NULL)
	{
		return 0;
	}
}

//二叉树叶子节点数
int LeafNum(Node* BinaryRoot)
{
	if (!BinaryRoot)
	{
		return 0;
	}
	else if ((BinaryRoot->Left == NULL) && (BinaryRoot->Right == NULL))
	{
		return 1;
	}
	else
	{
		return  (LeafNum(BinaryRoot->Left) + LeafNum(BinaryRoot->Right));
	}
}


int main()
{
	Node *BinaryRoot = NULL;
	BinaryRoot = createBinaryTree();
	
	cout<<"创建二叉树"<<endl;

	cout << "二叉树总节点数：" << NodeNum(BinaryRoot) << endl;

	cout << "二叉树深度：" << TreeDepth(BinaryRoot) << endl;

	cout << "二叉树叶子节点数：" << LeafNum(BinaryRoot) << endl;

	cout << "先序遍历:" << endl;
	PreOrderTraverse(BinaryRoot);
	cout << endl;

	cout << "中序遍历:" << endl;
	InOrderTraverse(BinaryRoot);
	cout << endl;

	cout << "后序遍历:" << endl;
	LastOrderTraverse(BinaryRoot);
	cout << endl;

	return 0;
}