数据结构--队列

// queue.cpp : Defines the entry point for the console application.
/*-----CODE FOR FUN---------------
-------CREATED BY Dream_Whui--
-------2015-1-25--------------------*/

#include "stdafx.h"
#include <stdlib.h>
#include <iostream>
using namespace std;

#define   TRUE              1
#define   FALSE             0
#define   OK                 1
#define   ERROR            0
#define   OVERFLOW   -2
#define   INFEASIBLE   -1

#define QElemType char //定义队列元素的类型

typedef struct QNode//定义结点的结构
{
    QElemType data;
    QNode *next;
}QNode,*QueuePtr;

typedef struct LinkQueue//定义队列结构
{
    QueuePtr front;
    QueuePtr rear;
}LinkQueue;

int InitQueue(LinkQueue &Q)//初始化队列
{
    Q.front = (QueuePtr)malloc(sizeof(QNode));
    if(!Q.front)
        return ERROR;
    Q.rear  = Q.front;
    Q.front->next = NULL;
    return OK;
}

int DestroyQueue(LinkQueue &Q)//销毁队列
{
    while(Q.front)
    {
        Q.rear = Q.front->next;
        free (Q.front);
        Q.front = Q.rear;
    }
    return OK;
}

int InsertQueue(LinkQueue &Q, QElemType e)//在对尾插入元素
{
    QueuePtr p = (QueuePtr)malloc(sizeof(QNode));
    if(!p)
        return ERROR;
    p->data = e;
    p->next = NULL;
    Q.rear->next = p;
    Q.rear = p;
    return OK;
}

int DeleteQueue(LinkQueue &Q, QElemType &e)//在对头删除元素
{
    if(Q.front == Q.rear)
        return ERROR;
    QueuePtr p = (QueuePtr)malloc(sizeof(QNode));
    if(!p)
        return ERROR;
    p = Q.front->next;
    e = p->data;
    Q.front->next = p->next;
    if(Q.rear == p)
        Q.rear = Q.front;
    free(p);
    return OK;
}

int QueueEmpty(LinkQueue &Q)//判断队列是否空
{
    if(Q.front == Q.rear)
        return OK;
    else
        return ERROR;
}

int QueueLength(LinkQueue &Q)//队列的长度
{
    QueuePtr p = Q.front;
    int num = 0;
    while(p != Q.rear)
    {
        num++;
        p = p->next;
    }
    return num;
}

QElemType GetHead(LinkQueue &Q, QElemType &e)//获取对头元素
{
    if(!QueueEmpty(Q))
        return e = Q.front->next->data;
    else
        return ERROR;
}

int main(int argc, char* argv[])
{
    LinkQueue Q;
    InitQueue(Q);
    InsertQueue(Q,'W');
    InsertQueue(Q,'A');
    InsertQueue(Q,'D');
    InsertQueue(Q,'F');
    QueuePtr p = Q.front;
    cout<<QueueLength(Q)<<endl;;
    while(p != Q.rear)
    {
        cout<<p->next->data<<" ";
        p = p->next;
    }
    cout<<endl;
    char e;
    DeleteQueue(Q,e);
    cout<<e<<endl;
    p = Q.front;
    while(p != Q.rear)
    {
        cout<<p->next->data<<" ";
        p = p->next;
    }
    cout<<endl;
    GetHead(Q,e);
    cout<<e<<endl;
    return 0;
}