关于《哈利波特》书的购买方案

思路：

购买时只需按(x*5+y)（0<y<5）,x套5本另外买y本（0<y<5）时价格最低。

代码：

#include <iostream>
using namespace std;

void main()
{
    int n;
    cout << "请输入要购买书的本数：" << endl; 
    cin >> n;

    int i;
    i = n/5;

    if (n < 5)
    {
        switch(n)
        {
        case 1:
            cout << "买1本书最低价格为8元"<< endl;
            break;
        case 2:
            cout << "买2本书最低价格为" << n*8*0.95 << "元"<< endl;
            break;
        case 3:
            cout << "买3本书最低价格为" << n*8*0.9 << "元"<< endl;
            break;
        case 4:
            cout << "买4本书最低价格为" << n*8*0.8 << "元"<< endl;
        }
    }
    else{
        switch(n%5)
        {
        case 0:
            cout << "买" << i << "套5本的" << endl;
            cout << "最低价格为：" << i*8*5*0.75<< endl;
            break;
        case 1:
            cout << "买" << i << "套5本的" << endl;
            cout << "外加" << n%5 << "本" << endl;
            cout << "最低价格为：" << i*8*5*0.75 + (n%5)*8<< endl;
            break;
        case 2:
            cout << "买" << i << "套5本的" << endl;
            cout << "外加" << n%5 << "本" << endl;
            cout << "最低价格为：" << i*8*5*0.75 + (n%5)*8*0.95 << endl;
            break;
        case 3:
            cout << "买" << i-1 << "套5本的" << endl;
            cout << "外加2套4本" << endl;
            cout << "最低价格为：" << (i-1)*8*5*0.75 + 2*4*8*0.8 << endl;
            break;
        case 4:
            cout << "买" << i << "套5本的" << endl;
            cout << "外加" << n%5 << "本" << endl;
            cout << "最低价格为：" << i*8*5*0.75 + (n%5)*8*0.8 << endl;
        }
    }
}