程序猿面试宝典（第三版）--队列的建立，測长，打印，入队，出队

编程实现队列的建立，測长，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)//队列中仅仅有一个元素
		{
			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);
}

执行结果：