链队列

//Queue.h

#ifndef QUEUE_H
#define QUEUE_H

#define OK 1
#define ERROR 0
typedef int QElemType;
typedef int Status;

typedef struct QNode {
    QElemType data;
    struct QNode *next;
}QNode,*QueuePtr;
typedef struct {
    QueuePtr front;  //队头指针
    QueuePtr rear;   //队尾指针
}LinkQueue;

Status InitQueue(LinkQueue &Q);
Status DestroyQueue(LinkQueue &Q);
Status ClearQueue(LinkQueue &Q);
Status QueueEmpty(LinkQueue Q);
int QueueLength(LinkQueue Q);
Status GetHead(LinkQueue Q, QElemType &e);
Status EnQueue(LinkQueue &Q, QElemType e);//插入队尾元素
Status DeQueue(LinkQueue &Q, QElemType &e);//删除队头元素
Status QueueTraverse(LinkQueue Q);
#endif

//Queue.cpp

#include"Queue.h"
#include<iostream>
#include<cstdlib>
using namespace std;

Status InitQueue(LinkQueue &Q)
{
    //构造空队列
    Q.front = Q.rear = (QueuePtr)malloc(sizeof(QNode));
    if (!Q.front)
        exit(OVERFLOW);
    Q.front->next = NULL;
    return OK;
}
Status DestroyQueue(LinkQueue &Q)
{
    while (Q.front)
    {
        Q.rear = Q.front->next;
        free(Q.front);
        Q.front = Q.rear;
    }
    return OK;
}
Status ClearQueue(LinkQueue &Q)
{
//    Q.rear = Q.front;
    DestroyQueue(Q);
    InitQueue(Q);
    return OK;
}
Status QueueEmpty(LinkQueue Q)
{
    if (Q.front == Q.rear)
        return OK;
    return ERROR;
}
int QueueLength(LinkQueue Q)
{
    QueuePtr temp = Q.front;
    int i = 0;
    while (temp != Q.rear)
    {
        temp = temp->next;
        i++;
    }
    return i;
}
Status GetHead(LinkQueue Q, QElemType &e)
{
    if (QueueEmpty(Q))
        return ERROR;
    e = Q.front->next->data;
    return OK;
}
Status EnQueue(LinkQueue &Q, QElemType e)
{
    QueuePtr P = (QueuePtr)malloc(sizeof(QNode));
    if (!P)
        exit(OVERFLOW);
    P->data = e;
    P->next = NULL;
    Q.rear->next = P;
    Q.rear = P;
    return OK;
}
Status DeQueue(LinkQueue &Q, QElemType &e)
{
    if (QueueEmpty(Q))
        return ERROR;
    QueuePtr P = Q.front->next;
    e = P->data;
    Q.front->next = P->next;
    if (Q.rear == P)
        Q.rear = Q.front;
    free(P);
    return OK;
}
Status QueueTraverse(LinkQueue Q)
{
    if (QueueEmpty(Q))
    {
        cout << "Empty!" << endl;
        return ERROR;
    }
    QueuePtr temp = Q.front;
    while (temp != Q.rear)
    {
        temp = temp->next;
        cout << temp->data << " ";
    }
    cout << endl;
    return OK;
}

//Main.cpp

#include"Queue.h"
#include<iostream>
using namespace std;
int main()
{
    LinkQueue LQ;
    InitQueue(LQ);
    QElemType temp;
    QElemType temp2;
    cout << QueueEmpty(LQ) << endl;
    EnQueue(LQ, 2);
    EnQueue(LQ, 7);
    EnQueue(LQ, 1);
    EnQueue(LQ, 5);
    EnQueue(LQ, 2);
    EnQueue(LQ, 0);
    QueueTraverse(LQ);
    DeQueue(LQ, temp);
    cout << "temp = " << temp << endl;
    QueueTraverse(LQ);
    cout << "length：" << QueueLength(LQ)<<endl;
    GetHead(LQ, temp);
    cout << "head = " << temp << endl;
//    DestroyQueue(LQ);
    ClearQueue(LQ);
    cout << "after Destroy LQ: " << endl;
    QueueTraverse(LQ);
    cout << "length：" << QueueLength(LQ) << endl;
    GetHead(LQ, temp2);
    cout << "head = " << temp2 << endl;
    system("pause");
    return 0;
}