程序员面试宝典（第三版）--队列的建立，测长，打印，入队，出队

#include<iostream>
#include<stdio.h>
#include<string.h>
#include<conio.h>
using namespace std;

typedef struct student
{
int data;
struct student *next;
}node;

typedef struct linkqueue
{
node *front;
node *rear;
}queue;

queue *create()
{
queue *q;
q=new queue;
q->front=NULL;
q->rear=NULL;
return q;
}
int length(queue *HQ)
{
if(HQ==NULL||HQ->rear==NULL)
{
cout<<"队列的长度为：0"<<endl;//////空队列
return 0;
}

int i=0;
node *p;
p=HQ->front;
while(p!=NULL)
{
p=p->next;
i++;
}
cout<<"队列的长度为："<<i<<endl;//////更新队列的长度
return i;
}

void print(queue *HQ)
{
node *p;
p=HQ->front;
cout<<"队列中的元素：";//////
if(p==NULL)
{
cout<<"空队列"<<endl;//////
return ;
}
while(p!=NULL)
{
cout<<p->data<<" ";//打印
p=p->next;
}
cout<<endl;
}

queue *insert(queue *HQ,int num)
{
node *s;

s=(node *)malloc(sizeof(node));
s->data=num;
s->next=NULL;
cout<<s->data<<"入队；";//////
if(HQ->front==NULL)//if(HQ->rear==NULL)//在空队列中进行元素入队操作
{
HQ->front=s;
HQ->rear=s;
}
else
{
HQ->rear->next=s;
HQ->rear=s;
}
cout<<endl;
return HQ;
}

queue *dele(queue *HQ)
{
node *p;int x;
cout<<"出队：";//////
if(HQ->front==NULL)//HQ->reat==NULL//在空队列中进行元素出队操作
printf("空队列");
else
{
x=HQ->front->data;
p=HQ->front;
cout<<x;
if(HQ->front==HQ->rear)//队列中只有一个元素
{
HQ->front=NULL;
HQ->rear=NULL;
}
else
{
HQ->front=HQ->front->next;
}
free(p);
}
cout<<endl;
return HQ;
}

void main()
{
queue *HQ;
HQ=create();
HQ=dele(HQ);//对空队列进行出队操作
int n;
HQ=insert(HQ,10);//入队
HQ=insert(HQ,2);
HQ=insert(HQ,3);
HQ=insert(HQ,4);
HQ=insert(HQ,5);
HQ=insert(HQ,6);
n=length(HQ);
print(HQ);
HQ=dele(HQ);//出队
HQ=dele(HQ);
HQ=dele(HQ);
HQ=dele(HQ);
HQ=dele(HQ);
HQ=dele(HQ);
n=length(HQ);
print(HQ);
HQ=dele(HQ);//对空队列进行出队操作
n=length(HQ);
print(HQ);
}