课堂练习：购买促销书籍问题

#include<iostream>
using namespace std;
float priceLowest;
void f(int bookNum)
{
	int N;
	N=bookNum%5;
	switch(N)
	{
		case 0:
			priceLowest=bookNum*8*0.75;
			break;
		case 1:
			priceLowest=(bookNum-N)*8*0.75+8;
			break;
		case 2:
			priceLowest=(bookNum-N)*8*0.75+2*8*0.95;
			break;
		case 3:
			priceLowest=(bookNum-N)*8*0.75+4*8*0.8*2-5*8*0.75;
			if(bookNum<5)
			{
				priceLowest+=0.4;
			}
			break;
		case 4:
			priceLowest=(bookNum-N)*8*0.75+4*8*0.8;
			break;
		default:
			cout<<"Error!"<<endl;
			
	}
}
void main()
{
	int q=0;
	while(q==0)
	{
		int bookNum;
		cout<<"请输入购买数量:";
		cin>>bookNum;
		f(bookNum);
		cout<<"最低价格为:"<<priceLowest<<endl;
		cout<<"是否继续测试?(输入0继续)";
		cin>>q;
	}
}