C语言数据结构编程练习-通过单链表实现队列的操作

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <assert.h>

/*
创建队列需要定义两个结构体
1.一个用来保存节点的链式结构
2、一个用来记录队头和队尾
*/

typedef int elementType;
typedef struct QueueListNode
{
	elementType value;
	struct QueueListNode* next;
}QNode;
typedef struct Queue_List
{
    QNode* head;//队头 
    QNode* tail;//队尾
}Queue;

void print_menu();
void init_queue(Queue* QueueList);
bool is_empty(Queue QueueList);
void out_queue(Queue* QueueList);
void enter_queue(Queue* QueueList);
void print_queue(Queue QueueList);
int getNum_queue(Queue QueueList);


int main()
{
    int order = 0;

    Queue QueueList;
    print_menu();
    while (1)
    {
        printf("请输入操作指令:");
        scanf(" %d", &order);
        switch (order)
        {
        case 1:
            //初始化队列
            
            init_queue(&QueueList);
            break;
        case 2:
            //判空
            is_empty(QueueList);
            break;
        case 3:
            //入队，即队列尾插
            enter_queue(&QueueList);
            break;
        case 4:
            //出列，即队列头删
            out_queue(&QueueList);
            break;
        case 5:
            //队列遍历
            print_queue(QueueList);
            break;
        case 6:
            //获取队列的元素个数
            printf("队列有%d个元素\n", getNum_queue(QueueList));
            break;
        case 7:
            //获取头节点元素
            is_empty(QueueList) ? ptintf("空队列\n") : printf("队列头元素为：%d\n", QueueList.head->value);
            break;
        case 8:
            //获取尾节点元素
            is_empty(QueueList) ? ptintf("空队列\n") : printf("队列尾元素为：%d\n", QueueList.tail->value);
            break;
        case 9:
            //退出
            return;
        default:
            printf("输入指令有误，请重新输入\n");
            break;
        }
    }

	return 0;
}

void print_menu()
{
    printf("操作指令如下:\n");
    printf("1----初始化空队列\n");
    printf("2----判断队列是否为空\n");
    printf("3----入列(队尾插入)\n");
    printf("4----出列(队头删除)\n");
    printf("5----遍历队列\n");
    printf("6----获取队列中元素个数\n");
    printf("7----获取队头元素\n");
    printf("8----获取队尾元素\n");
    printf("9----退出\n");
}

//初始化空队列
void init_queue(Queue* QueueList)
{
    assert(QueueList);
    QueueList->head = NULL;
    QueueList->tail = NULL;
    printf("初始化成功\n");
}

//判空   空返回1  否则返回0
bool is_empty(Queue QueueList)
{
    /*if (QueueList.tail == NULL)
    {
        return true;
    }
    return false;*/

    //优化写法
    return QueueList.tail == NULL;
}

//入队，尾插
void enter_queue(Queue* QueueList)
{
    QNode* newnode = (QNode*)malloc(sizeof(QNode));
    assert(newnode);
    memset(newnode, 0, sizeof(QNode));

    elementType val;
    printf("请输入要入队的元素值:");
    scanf(" %d", &val);
    newnode->value = val;
    newnode->next = NULL;

    if (is_empty(*QueueList))
    {
        //如果队列是空
        QueueList->head = newnode;
        QueueList->tail = newnode;
    }
    else
    {
        //队列非空，尾插
        QueueList->tail->next = newnode;//将新节点插到尾部
        QueueList->tail = newnode;//更新尾节点
    }

    printf("入队成功\n");
}

//出队  头删
void out_queue(Queue* QueueList)
{
    if (is_empty(*QueueList))
    {
        printf("队列为空，无法出列\n");
        return;
    }
    QNode* temp = QueueList->head->next;//保存次头节点
    if (temp == NULL)
    {
        //说明队列里面只有一个元素  删完后就为空队列
        free(QueueList->head);
        QueueList->head = NULL;
        QueueList->tail = NULL;
    }
    else
    {
        free(QueueList->head);
        QueueList->head = temp;
    }

    printf("出列成功\n");
}

//打印遍历队列
void print_queue(Queue QueueList)
{
    if (is_empty(QueueList))
    {
        printf("空队列，无法打印\n");
        return;
    }
    QNode* temp = QueueList.head;
    while (temp != NULL)
    {
        printf(" %d ", temp->value);
        temp = temp->next;
    }
    printf("\n");
}

//获取队列的个数
int getNum_queue(Queue QueueList)
{
    int count = 0;
    if (is_empty(QueueList))
    {
        return count;
    }
    QNode* temp = QueueList.head;
    while (temp != NULL)
    {
        count++;
        temp = temp->next;
    }


    return count;
}