算法：某市规定如下用水收费标准：每户一月用水不超过6立方米时，水费按“基准费”收，每立方米2.4元

#include "stdio.h"

#define STANDARD_EXPENSES 2.4
#define ADJUSTMENT_EXPENSES 6

int main(void)
{
float water = 0;

printf("本月用水量：");
scanf_s("%f", &water);

switch (water >= 6)
{
case 1:
printf("本月水费为：%f\n", 6 * STANDARD_EXPENSES + (water - 6) * ADJUSTMENT_EXPENSES);
break;
case 0:
printf("本月水费为：%f\n", water * STANDARD_EXPENSES);
break;
}

return 0;
}