C语言数据结构详细解析二叉树的操作

typedef char BTDataType;
typedef struct BinaryTreeNode {
	struct BinaryTreeNode* left;
	struct BinaryTreeNode* right;
	BTDataType data;
}BTNode;
int main()
{
	BTNode* A = (BTNode*)malloc(sizeof(BTNode));
	A->data = 'A';
	A->left = NULL;
	A->right = NULL;
	BTNode* B = (BTNode*)malloc(sizeof(BTNode));
	B->data = 'B';
	B->left = NULL;
	B->right = NULL;
	BTNode* C = (BTNode*)malloc(sizeof(BTNode));
	C->data = 'C';
	C->left = NULL;
	C->right = NULL;
	BTNode* D = (BTNode*)malloc(sizeof(BTNode));
	D->data = 'D';
	D->left = NULL;
	D->right = NULL;
	BTNode* E = (BTNode*)malloc(sizeof(BTNode));
	E->data = 'E';
	E->left = NULL;
	E->right = NULL;
	A->left = B;
	A->right = C;
	B->left = D;
	B->right = E;
	LevelOrder(A);
}

//前序
void PrevOrder(BTNode* root)
{
	if (root == NULL)
	{
		//为了结果更加直观，将NULL打印
		printf("NULL ");
		return;
	}
	//先打印根的数据
	printf("%c ", root->data);
	//遍历左子树
	PrevOrder(root->left);
	//遍历右子树
	PrevOrder(root->right);
}

void MidOrder(BTNode* root)
{
	//为了结果更加直观，将NULL打印
	if (root == NULL)
	{
		printf("NULL ");
		return;
	}
	MidOrder(root->left);
	printf("%c ", root->data);
	MidOrder(root->right);
}

void PostOrder(BTNode* root)
{
	if (root == NULL)
	{
		printf("NULL ");
		return;
	}
	PostOrder(root->left);
	PostOrder(root->right);
	printf("%c ", root->data);
}

void LevelOrder(BTNode* root)
{
	//创建队列q
	Queue q;
	//初始化队列
	QueueInit(&q);
	//如果根结点不为空，将根节点入队列
	if (root) QueuePush(&q, root);
	//进行循环，直到队列为空
	while (!QueueEmpty(&q))
	{
		//获取队列的第一个数据，并打印
		QDataType front = QueueFront(&q);
		printf("%c ", front->data);
		//对头数据出队列
		QueuePop(&q);
		//如果左子树不为空，左子树入队列
		if (front->left != NULL)
		{
			QueuePush(&q, front->left);
		}
		//如果右子树不为空，右子树入队列
		if (front->right != NULL)
		{
			QueuePush(&q, front->right);
		}
	}
}

int BTSize(BTNode* root)
{
	return root == NULL ? 0 :1 + BTSize(root->left) + BTSize(root->right);
}

int BTLeafSize(BTNode* root)
{
	if (root == 0) return 0;
	return root->left == NULL && root->right == NULL ? 1 : BTLeafSize(root->right) + BTLeafSize(root->left);
}

int maxDepth(BTNode* root)
{
	if (root == NULL)
		return 0;
	return 1 + fmax(maxDepth(root ->left),maxDepth(root ->right));
}

//二叉树的销毁
//传二级指针是为了改变指针的指向
void DistoryTree(BTNode** root)
{
	if (*root == NULL)
	{
		return;
	}
	DistoryTree(&(*root)->left);
	DistoryTree(&(*root)->right);
	free(*root);
	*root = NULL;
}