exercise8-1.cpp

/*）某货物单价100元，若买100个及以上按九五折优惠，500个及以上按九折计算。输入购买个数，求总款数(结果保留两位有效数字),当输入购买个数为非法（小于0）时，给出提示信息。（选择）*/
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
    float price, discount, amount;
    int count;
    cout << "输入购买件数:" << endl;
    cin >> count;
    cout << "输入单价:" << endl;
    cin >> price;

    if (count <= 0)
        cout << "输入购买件数非法!" << endl;
    else
    {
        if (count < 100) // count > 0 && count < 100
            discount = 1;
        else if (count < 500) // count >= 100 && count < 500
            discount = 0.95;
        else                   // count >= 500 
            discount = 0.9;

        amount = price * discount * count;
        cout << setiosflags(ios::fixed) << setprecision(2) << "总款为:" << amount << endl;
    }
   


    // if(count <= 0){
    //     cout << "非法";
    //     return 0;
    // }

    // if(count > 0 && count < 100){
    //     discount = 1;
    // }

    // if(count >= 100 && count < 500){
    //     discount = 0.95;
    // }

    // if(count >= 500){
    //     discount = 0.9;
    // }

    return 0;

}