题解 | #网购#

#include <stdio.h>

int main() 
{
	double price = 0.0;//价格
	int  month = 0;//月
	int day = 0;//日
	int flag = 0;//是否有优惠卷
	scanf("%lf %d %d %d", &price, &month, &day, &flag);
	double cut = 0.0;//折扣
	double sum = 0.0;//计算价格
	if (month == 11 && day == 11) 
	{
		cut = 0.7;
	}
	else if (month == 12 && day == 12) 
	{
		cut = 0.8;
	}
	sum = price * cut - flag * 50;
	if (sum < 0.0) 
	{
		printf("%.2lf\n", 0.0);
	}
	else 
	{
		printf("%.2lf\n", sum);
	}
	return 0;
}