单向链表队列

实现单向链表队列的，创建，入队，出队，遍历，长度，销毁。

 queue.h

#ifndef __QUEUE_H__
#define __QUEUE_H__

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define max 30
typedef int datatype;
typedef struct node
{
	union
	{
		int len;
		datatype data;
	};
	struct node *next;
}node;
typedef struct loop
{
	node *front;
	node *tail;
}queue, *queue_p;

queue_p create();
int empty(queue_p Q);
int full(queue_p Q);
void add(queue_p Q, datatype num);
void show(queue_p Q);
void pop(queue_p Q);
void lenth(queue_p Q);
void free_queue(queue_p Q);

#endif

main.c 

#include "queue.h"

int main()
{
	queue_p Q = create();
	add(Q, 1);
	add(Q, 2);
	add(Q, 3);
	add(Q, 4);
	show(Q);
	pop(Q);
	show(Q);
	lenth(Q);
	free_queue(Q);

	
	return 0;
}

queue.c 

#include "queue.h"

//创建

queue_p create()
{
	queue_p Q = (queue_p)malloc(sizeof(queue));
	if(NULL == Q)
	{
		printf("失败\n");
		return NULL;
	}
	Q -> front  = NULL;
	Q -> tail = NULL;
	Q -> front = (node*)malloc(sizeof(node));
	if(Q -> front == NULL)
	{
		printf("失败\n");
		free(Q);
		Q = NULL;
		return NULL;
	}

	Q -> front -> len = 0;
	Q -> tail = Q -> front;

	return Q;

}
//判空
int empty(queue_p Q)
{
	if(NULL == Q)
	{
		printf("失败");
		return 0;
	}
    return Q -> tail == Q -> front;
}

//入队
void add(queue_p Q, datatype data)
{
	if(NULL == Q)
	{
		printf("失败\n");
		return;
	}
	node * p = (node *)malloc(sizeof(node));
	p -> data = data;
	Q -> tail -> next = p;
	Q -> tail = p;
	Q -> front -> len++;

}
//遍历
void show(queue_p Q)
{
	if(NULL == Q || empty(Q))
	{
		printf("空\n");
		return;
	}
	printf("队列的元素为：");
	node *p = Q -> front -> next;
	do
	{
		printf("%d", p -> data);
		p = p -> next;
	}while(p != NULL);
	putchar(10);
}

//出队
void pop(queue_p Q)
{
	if(NULL == Q || empty(Q))
	{
		printf("空");
		return;
	}
	node *p = Q -> front -> next;
	Q -> front -> next = p -> next;
	if(Q -> front -> next == NULL)
	{
		Q -> tail = Q -> front;
	}
	free(p);
	p = NULL;
	Q -> front -> len--;
	
}
//队长
void lenth(queue_p Q)
{
	if(NULL == Q)
	{
		printf("失败");
		return;
	}
	printf("队列长度为：%d\n", Q -> front -> len);
}
//销毁
void free_queue(queue_p Q)
{
	if(NULL == Q)
	{
		printf("销毁失败\n");
		return;
	}
	while(!empty(Q))
	{
		pop(Q);
	}

	free(Q -> front);
	
	
	printf("销毁成功\n");
}

实现效果