//不带头结点的链式队列
#include <iostream>
#include <stdlib.h>
#include <stdio.h>

using namespace std;

  （出队操作）    node1-->node2 --> node3 --> ....-->noden（入队操作）
//                          1                                                  1
//                              first                                              rear

typedef struct Node
{
    int data;
    struct Node *next;
}node;
typedef struct Queue    //notice :队列的数据结构只是包括两个节点指针（头和尾）；
{
    node* first;
    node* rear;
}queue;

//队列的插入操作。注意：队列是从rear部插入
queue* insert(queue* My_queue,int x)
{
    node* s;
    s = (node*)malloc(sizeof(node));
    s->data = x;
    s->next = NULL;
    //分为队列为空与队列非空两种。
    if(NULL == My_queue->rear)
    {
        My_queue->first = s;
        My_queue->rear = s;
    }
    else
    {
        My_queue->rear->next = s;
        My_queue->rear = s;
    }
    return My_queue;
}

//队列的删除操作。注意：删除是在first部的操作。
queue* del(queue* My_queue)
{
    node* p;
    int x;
    //判断队列是否为空
    if(My_queue->first == NULL)
    {
        printf("Noting to delete!!!WRONG\n");
    }
    else
    {
        x = My_queue->first->data;
        p = My_queue->first;
        //判断队列是否删除后为空。（易忽略）
        if(My_queue->first == My_queue->rear)
        {
            My_queue->first = NULL;
            My_queue->rear = NULL;
            free(p);
        }
        else
        {
            My_queue->first = My_queue->first->next;
            free(p);
        }
        return My_queue;
    }
}

typedef int datatype;
typedef struct node
{
    datatype data;
    struct node* next;
}listnode, *linknode;
typedef struct
{
    linknode front;
    linknode rear;
}linkqueue;

//不带头结点的链队入队实现：
void enqueue(linkqueue* q, datatype x){
    linknode p = (linknode)malloc(sizeof(listnode));
    p->data = x;
    p->next = NULL;
    if(q->front == NULL)
    {
        q->front = p;
        q->rear = p;
        return;
    }
    q->rear->next = p;
    q->rear = p;
}