规定大小的循环队列

#include 
#define Maxsize 10
static bool flag = 0;
static int det = 0;

typedef struct Queue {
	int val[Maxsize];
	int front, tail;
}Queue;

int initQueue(Queue& Q) {
	Q.front = Q.tail = 0;
	return 1;
}

int Enqueue(Queue& Q, int num) {
	if ((flag) & (Q.front == Q.tail)) {
		printf("queue is full!\n");
		det = 1;
		return 0;
	}
	Q.val[Q.front++] = num;
	Q.front %= 10;
	if (Q.tail == Q.front) {
		det = 1;
	}
	flag = 1;
	return 1;
}

int Dequeue(Queue& Q) {
	if ((!flag) & (Q.front == Q.tail)) {
		printf("queue is empty!\n");
		return 0;
	}
	Q.tail++;
	Q.tail %= 10;
	det = 0;
	flag = 0;
	return 1;
}

int main() {
	Queue Q;
	int seq, num;
	int length;
	int i;
	initQueue(Q);
	while (true) {
		printf("1.Dequeue\n2.Enqueue\n");
		printf("please enter your option:");
		scanf_s("%d", &seq);
		switch (seq)
		{
		case(1):
			Dequeue(Q);
			break;
		case(2):
			printf("please enter the num:");
			scanf_s("%d", &num);
			Enqueue(Q, num);
			break;
		default:
			break;
		}
		length = (Q.front - Q.tail+ Maxsize) % Maxsize + 10*det;
		printf("length:%d\n", length);
		printf("\npresent queue is:\n");
		for (i = 0; i < length; i++) {
			printf("%d ", Q.val[(Q.tail + i) % Maxsize]);
		}
		printf("\n");
	}
	return 0;
}