[C++知识库]队列、树(二叉树的前中后序的实现，用递归和队列计算叶子节点和节点)，排序

头文件

#pragma once

#include <stdio.h>
#include <stdbool.h>
#include <assert.h>
#include <stdlib.h>
struct BinaryTreeNod;//前置申明

typedef struct BinaryTreeNode* QDataType;


typedef struct QueueNode
{
	struct QueueNode* next;
	QDataType data;
}QNode;

typedef struct Queue
{
	QNode* head;
	QNode* tail;
}Queue;

void QueueInit(Queue* pq);
void QueueDestory(Queue* pq);

// 队尾入
void QueuePush(Queue* pq, QDataType x);
// 队头出
void QueuePop(Queue* pq);
QDataType QueueFront(Queue* pq);
QDataType QueueBack(Queue* pq);
int QueueSize(Queue* pq);
bool QueueEmpty(Queue* pq);

队列功能

#include "Queue.h"

void QueueInit(Queue* pq)
{
	assert(pq);
	pq->head = pq->tail = NULL;
}

void QueueDestory(Queue* pq)
{
	assert(pq);

	QNode* cur = pq->head;
	while (cur)
	{
		QNode* next = cur->next;
		free(cur);
		cur = next;
	}

	pq->head = pq->tail = NULL;
}

// 队尾入
void QueuePush(Queue* pq, QDataType x)
{
	assert(pq);
	QNode* newnode = (QNode*)malloc(sizeof(QNode));
	if (newnode == NULL)
	{
		printf("malloc fail\n");
		exit(-1);
	}

	newnode->data = x;
	newnode->next = NULL;

	if (pq->tail == NULL)
	{
		pq->head = pq->tail = newnode;
	}
	else
	{
		pq->tail->next = newnode;
		pq->tail = newnode;
	}
}

// 队头出
void QueuePop(Queue* pq)
{
	assert(pq);
	assert(pq->head);

	// 1、一个
	// 2、多个
	if (pq->head->next == NULL)
	{
		free(pq->head);
		pq->head = pq->tail = NULL;
	}
	else
	{
		QNode* next = pq->head->next;
		free(pq->head);
		pq->head = next;
	}
}


QDataType QueueFront(Queue* pq)
{
	assert(pq);
	assert(pq->head);

	return pq->head->data;
}

QDataType QueueBack(Queue* pq)
{
	assert(pq);
	assert(pq->head);

	return pq->tail->data;
}

int QueueSize(Queue* pq)
{
	assert(pq);
	int size = 0;
	QNode* cur = pq->head;
	while (cur)
	{
		++size;
		cur = cur->next;
	}

	return size;
}

bool QueueEmpty(Queue* pq)
{
	assert(pq);
	return pq->head == NULL;
}

二叉树的前中后序的实现，用递归和队列计算叶子节点和节点

#define _CRT_SECURE_NO_DEPRECATE
#include<stdio.h>
#include<stdlib.h>
#include "Queue.h"
typedef char Datetype;
struct Node//左孩子，右兄弟
{

	struct Node* _firstchild;
	struct Node* _pNextBrother;
	Datetype _Date;
};


typedef struct BinaryTreeNode{
	struct BinaryTreeNode* left;
	struct BinaryTreeNode* right;
	Datetype date;
}BTNode;

void PrevOrder(BTNode* root)
{
	if (root == NULL){
		printf("NULL  ");
		return;

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

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

	}
	PrevOrder(root->left);
	PrevOrder(root->right);
	printf("%c  ", root->date);
}
//int* TreeSize(BTNode* root,int* psize)//遍历
//{
//
//	if (root == NULL){
//		return psize;
//	}
//	else
//	{
//		(*psize)++;
//	}
//	TreeSize(root->left, psize);
//	TreeSize(root->right, psize);
//	return psize;
//}

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

}
int TreeLeafSize(BTNode* root)//递归方法
{
	if (root == NULL)
	{
		return 0;
	}
	if (root->left == NULL && root->right == NULL)
	{
		return 1;
	}
	return TreeLeafSize(root->left) + TreeLeafSize(root->right);
}

void Levelorder(BTNode* root)//队列方法
{
	Queue q;//创建队列
	QueueInit(&q);//初始化
	if (root)//确保压入队列的二叉树不为空
		QueuePush(&q, root);//压入二叉树的第一个节点的指针（头结点的指针就是二叉树的全部）
	while (!QueueEmpty(&q))//确保循环时队列不为空
	{
		BTNode* front = QueueFront(&q);//二叉树的第一个节点的指针写为队列的第一个值
		printf("%c", front->date);
		QueuePop(&q);
		if (front->left)
		{
			QueuePush(&q,front->left);
		}
		if (front->right)
		{
			QueuePush(&q, front->right);
		}
	}
	printf("\n");	
	QueueDestory(&q);
}

int main()
{
	BTNode* A = (BTNode*)malloc(sizeof(BTNode));
	if (A == NULL)
		printf("内存分配失败");
	A->date = 'A';
	A->left = NULL;
	A->right = NULL;



	BTNode* B = (BTNode*)malloc(sizeof(BTNode));
	if (B == NULL)
		printf("内存分配失败");
	B->date = 'B';
	B->left = NULL;
	B->right = NULL;



	BTNode* C = (BTNode*)malloc(sizeof(BTNode));
	if (C == NULL)
		printf("内存分配失败");
	C->date = 'C';
	C->left = NULL;
	C->right = NULL;



	BTNode* D = (BTNode*)malloc(sizeof(BTNode));
	if (D == NULL)
		printf("内存分配失败");
	D->date = 'D';
	D->left = NULL;
	D->right = NULL;



	BTNode* E = (BTNode*)malloc(sizeof(BTNode));
	if (E == NULL)
		printf("内存分配失败");
	E->date = 'E';
	E->left = NULL;
	E->right = NULL;


	A->left = B;
	A->right = C;
	B->left = D;
	B->right = E;

	PrevOrder(A);
	printf("\n");
	InOrder(A);
	printf("\n");
	PostOrder(A);
	printf("\n");


	/*int size = 0;
	treesize(A, &size);
	printf("%d ",size);
	size = 0;
	treesize(B, &size);
	printf("%d ",size);*/


	int size = 0;
	/*size=TreeSize(A);
	printf("%d ", size);
	size=TreeSize(B);
	printf("%d ", size);*/
	size = TreeLeafSize(A);
	printf("%d \n", size);

	Levelorder(C);

	
}

排序

int main()
{
	int n=0;
	int arr[200];
	int i = 0;
	scanf("%d ", &n);
	for (i = 0; i<n; i++)
	{

		scanf("%d", &arr[i]);
	}

	for (i = 0; i<n - 1; i++)
	{
		int j = 0;
		for (j = 0; j<n - 1 - i; j++)
		{
			if (arr[j]>arr[j + 1])
			{
				int tmp;
				tmp = arr[j];
				arr[j] = arr[j + 1];
				arr[j + 1] = tmp;
			}
		}
	}
	for (i = 0; i<n; i++)
	{
		printf("%d ", arr[i]);
	}
}