链表实现队列出队和入队

队列需要两个链表结点来表示头和尾，入队可视为从队尾的链表结点插入一个新的结点，插入后需要将队尾指针后移，而出队则是查询队首结点的值，将队首指针后移，并将队首指针所指向的内存区域释放。

#include<iostream>
#include<stdio.h>

using namespace std;

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

typedef struct linkqueue
{
	node * first=NULL, *rear=NULL;
}queue;

queue * enqueue(queue * q, int x)
{
	node * p = (node *)malloc(sizeof(node));
	p->data = x;
	p->next = nullptr;

	if (q->rear == NULL)
	{
		q->rear = p;
		q->first = p;
	}
	else
	{
		q->rear->next = p;
		q->rear = p;
	}
	return q;
	
}


int popqueue(queue * q)
{
	if (q->first == NULL)
		cout << "队列溢出" << endl;
	else
	{
		node * p = q->first;
		int temp = p->data;
		q->first = p->next;
		free(p);
		return temp;
	}
}

void printqueue(queue * q)
{
	node *p = q->first;
	while (p!= NULL)
	{
		cout << p->data <<" ";
		p = p->next;
	}
	cout << endl;

}

int main(){
	queue q;
	enqueue(&q , 3);
	enqueue(&q, 5);
	enqueue(&q, 8);
	printqueue(&q);
	popqueue(&q);
	printqueue(&q);
	popqueue(&q);
	printqueue(&q);
	popqueue(&q);
	printqueue(&q);
	popqueue(&q);
	printqueue(&q);
	system("pause");
	return 0;
}