单链队列

一、Queue.h

#ifndef __Queue_h__
#define __Queue_h__

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <Windows.h>

typedef int DataType;

typedef struct QueueNode
{
    DataType _data;
    struct QueueNode* _next;
}QueueNode;

typedef struct Queue
{
    QueueNode* _head; //队头指针
    QueueNode* _tail; //队尾指针
}Queue;

void QueueInit(Queue* q);
void QueueDestroy(Queue* q);
void QueuePush(Queue* q, DataType x);
void QueuePop(Queue* q);
DataType QueueFront(Queue* q);
DataType QueueBack(Queue* q);
size_t QueueSize(Queue* q);
int QueueEmpty(Queue* q);
void QueuePrint(Queue* q);

#endif __Queue_h__

二、Queue.c

#define _CRT_SECURE_NO_WARNINGS 1

#include "Queue.h"

//初始化
void QueueInit(Queue* q)
{
    assert(q);
    q->_head = q->_tail = (QueueNode*)malloc(sizeof(QueueNode));
    if (q->_head == NULL)
    {
        printf("初始化失败\n");
    }
    else
    {
        q->_head->_next = NULL;
        printf("初始化成功\n");
    }
}

//销毁
void QueueDestroy(Queue* q)
{
    assert(q);
    while (q->_head)
    {
        q->_tail = q->_head->_next;
        free(q->_head);
        q->_head = q->_tail;
    }
    printf("销毁成功\n");
}

//入队
void QueuePush(Queue* q, DataType x)
{
    QueueNode* newnode = (QueueNode*)malloc(sizeof(QueueNode));
    if (newnode == NULL)
    {
        printf("插入失败\n");
    }
    else
    {
        newnode->_data = x;
        newnode->_next = NULL;
        q->_tail->_next = newnode;
        q->_tail = newnode;
        printf("插入成功\n");
    }
}

//出队
void QueuePop(Queue* q)
{
    if (q->_head == q->_tail)
    {
        printf("该队列为空\n");
    }
    else
    {
        QueueNode* next = q->_head->_next;
        q->_head->_next = next->_next;
        if (q->_tail == next)
        {
            q->_tail = q->_head;
        }
        free(next);
        printf("删除成功\n");
    }
}

//获取队头元素
DataType QueueFront(Queue* q)
{
    if (q->_head == q->_tail)
    {
        printf("该队列为空\n");
    }
    else
    {
        return q->_head->_next->_data;
    }
}

//获取队尾元素
DataType QueueBack(Queue* q)
{
    if (q->_head == q->_tail)
    {
        printf("该队列为空\n");
    }
    else
    {
        return q->_tail->_data;
    }
}

//队列长度
size_t QueueSize(Queue* q)
{
    assert(q);
    QueueNode* cur = q->_head->_next;
    int count = 0;
    while (cur)
    {
        count++;
        cur = cur->_next;
    }
    return count;
}

//判空
int QueueEmpty(Queue* q)
{
    if (q->_head == q->_tail)
    {
        return 0;
    }
    return 1;
}

//输出
void QueuePrint(Queue* q)
{
    if (q->_head == q->_tail)
    {
        printf("该队列为空\n");
    }
    else
    {
        QueueNode* cur = q->_head->_next;
        while(cur)
        {
            printf("%d ", cur->_data);
            cur = cur->_next;
        }
        printf("\n");
    }
}