C语言：switch处理打折问题

#include
int main()
{
	int p = 0;
	double s, d = 0;
	printf("原价:");
	scanf_s("%d", &p);
	switch (p / 200)
	{
	case 0:
		d = 0;
		break;
	case 1:
		d = 0.05;
		break;
	case 2:
		d = 0.1;
		break;
	case 3:
	case 4:
		d = 0.15;
		break;
	default:
		d = 0.2;
		break;
	}
    s = p - p * d;
	printf("折后价:%f\n", s);
	return 0;
}