[数据结构与算法]C语言建立队列、入队、出队

定义队列结构

typedef struct QUEUE
{
	int *array;
	int front;
	int rear;
}Q;

建立队列

Q* creatqueue(int len)
{
	Q* que = (Q*)malloc(sizeof(Q));
	if (que)
	{
		que->array = (int*)malloc(sizeof(int) * len);
		if (que->array == NULL)
			return NULL;
		que->front = que->rear = 0;
	}
	return que;
}

入队

int in(Q* que,int data,int len)
{
	if (que->rear == len)
		return 0;
	que->array[++que->rear] = data;
	return que->rear;
}

出队

int out(Q* que)
{
	if (que->front != que->rear)
	{
		return que->array[++que->front];
		que->array[que->front] = 0;
	}
	else return NULL;
}

主函数

void main()
{
	int len, n, data;
	printf("请输入队列最大长度：\n");
	scanf_s("%d", &len);
	Q* que=creatqueue(len);
	printf("请输入入队元素个数：\n");
	scanf_s("%d", &n);
	printf("请输入入队元素：\n");
	for (int i = 0; i < n; i++)
	{
		scanf_s("%d", &data);
		if (in(que, data, len) == 0)
			break;
	}
	//入队↑，出队↓
	printf("请输入出队元素个数：");
	scanf_s("%d", &n);
	for (int i = 0; i < n; i++)
	{
		if(data=out(que))
			printf("%d ",data);
	}
}