C实现队列

头文件

#define  _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
#include<stdbool.h>
typedef int QDataType;
typedef struct QueueNode
{
	QDataType data;
	struct QueueNode* next;

}QNode;
typedef struct Queue
{
	QNode* head;
	QNode* tail;
	int size;
}Queue;
//初始化
void QueueInit(Queue* pq);
//销毁
void QueueDestroy(Queue* pq);
//队尾入队列
void QueuePush(Queue* pq, QDataType x);
//队头出队列
void QueuePop(Queue* pq);
//查看队头元素
QDataType QueueFront(Queue* pq);
//查看队尾元素
QDataType QueueBack(Queue* pq);
///检测队列是否为空，如果为空返回非零结果，如果非空返回0
bool QueueEmpty(Queue* pq);
//个数
int QueueSize(Queue* pq);

功能实现

#include "Queue.h"
void QueueInit(Queue* pq)
{
	assert(pq);
	pq->head = NULL;
	pq->tail = NULL;
	pq->size = 0;
}
void QueueDestroy(Queue* pq)
{
	assert(pq);
	QNode* cur = pq->head;
	while (cur)
	{
		QNode* tmp = cur;
		cur = cur->next;
		free(tmp);
	}
	pq->head = pq->tail = NULL;
	pq->size = 0;
}
void QueuePush(Queue* pq, QDataType x)
{
	assert(pq);
	QNode* newnode = (QNode*)malloc(sizeof(QNode));
	if (newnode == NULL)
	{
		perror("malloc fail");
		return;
	}
	newnode->data = x;
	newnode->next = NULL;

	if (pq->tail == NULL)
	{
		pq->head = pq->tail = newnode;
	}
	else
	{
		pq->tail->next = newnode;
		pq->tail = newnode;
	}
	pq->size++;
}
void QueuePop(Queue* pq)
{
	assert(pq);
	assert(!QueueEmpty(pq));
	if (pq->head->next == NULL)
	{
		free(pq->head);
		pq->head = pq->tail = NULL;
	}
	else
	{
		QNode* tmp = pq->head;
		pq->head = pq->head->next;
	}
	pq->size--;
}
QDataType QueueFront(Queue* pq)
{
	assert(pq);
	assert(!QueueEmpty(pq));
	return pq->head->data;
}
QDataType QueueBack(Queue* pq)
{
	assert(pq);
	assert(!QueueEmpty(pq));
	return pq->tail->data;
}
bool QueueEmpty(Queue* pq)
{
	assert(pq);
	return pq->head == NULL && pq->tail == NULL;//Ϊ1Ϊ0
}
int QueueSize(Queue* pq)
{
	assert(pq);
	return pq->size;
}

运行

#include "Queue.h"
int main()
{
	Queue q;
	QueueInit(&q);
	QueuePush(&q, 1);
	QueuePush(&q, 2);
	QueuePush(&q, 3);
	QueuePush(&q, 4);
	printf("%d\n", QueueSize(&q));
	printf("%d\n", QueueEmpty(&q));
	printf("%d\n", QueueFront(&q));
	printf("%d\n", QueueBack(&q));
	QueuePop(&q);
	printf("%d\n", QueueSize(&q));
	printf("%d\n", QueueFront(&q));
	printf("%d\n", QueueBack(&q));
	QueuePush(&q, 5);
	QueuePush(&q, 6);
	QueuePush(&q, 7);
	printf("%d\n", QueueSize(&q));
	printf("%d\n", QueueFront(&q));
	printf("%d\n", QueueBack(&q));
	while(!QueueEmpty(&q))
	{
		printf("%d ", QueueFront(&q));
		QueuePop(&q);
	}
	printf("\n");
	printf("%d\n", QueueSize(&q));
	printf("%d\n", QueueEmpty(&q));
	QueueDestroy(&q);
	return 0;
}