题解 | #计算商品打折结算金额#

#include <iostream>
#include <iomanip>
using namespace std;

int main() {
    
    double price;
    cin >> price;

    double cost = 0.0;

    // 商品打折，条件语句,分类讨论
    if(price < 100)
        cost = price;
    if(100 <= price && price < 500)
        cost = price*0.9;
    if(500 <= price && price < 2000)
        cost = price*0.8;
    if(2000 <= price && price < 5000)
        cost = price*0.7;
    if(5000 <= price)
        cost = price*0.6;
    
    cout << setiosflags(ios::fixed) << setprecision(1) << cost << endl; //防止小数点后只有一位且为0时显示为e浮点数，setprecision(n)有n位小数
 
    return 0;
}