java多态和接口题，要代码和运行截图

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面向对象（2）（接口和多态、Random类使用）小明现在想点外卖，美团外卖的优惠劵规则是：满50随机生成15以内的随机优惠劵（100两张，以此类推），配送费5元；饿了吗的优惠劵规则：满100随机生成25以内的优惠劵一张，配送费10元。

外卖平台接口类

public interface Takeaway {
    // 计算总费用
    double getTotalMoney(List<Shop> shops);
    // 计算优惠费用
    double getDiscountMoney(double totalMoney);
}

美团实现类

public class Meituan implements Takeaway {
    @Override
    public double getTotalMoney(List<Shop> shops) {
        double sum = 0;
        for (Shop shop : shops) {
            sum += shop.getPrice() * shop.getCount();
        }
        return sum;
    }
    @Override
    public double getDiscountMoney(double totalMoney) {
        Random r = new Random();
        double sum = 0;
        int n = (int) (totalMoney / 50);
        for (int i = 0; i < n; i++) {
            // 随机生成15以内优惠券并相加，精确到小数点后两位
            sum += (r.nextInt(1500) + 1) / 100.0;
        }
        return sum;
    }
}

饿了么实现类

public class Eleme implements Takeaway {
    @Override
    public double getTotalMoney(List<Shop> shops) {
        double sum = 0;
        for (Shop shop : shops) {
            sum += shop.getPrice() * shop.getCount();
        }
        return sum;
    }
    @Override
    public double getDiscountMoney(double totalMoney) {
        Random r = new Random();
        double sum = 0;
        if (totalMoney > 100) {
            // 随机生成25以内优惠券并相加，精确到小数点后两位
            sum = (r.nextInt(2500) + 1)/100.0;
        }
        return sum;
    }
}

测试类main方法

public static void main(String[] args) {
    Shop s1 = new Shop(30, 3);
    Shop s2 = new Shop(12, 3);
    Shop s3 = new Shop(13, 2);
    Shop s4 = new Shop(15, 3);
    List<Shop> list = new ArrayList<>();
    list.add(s1);
    list.add(s2);
    list.add(s3);
    list.add(s4);
    Takeaway t1 = new Meituan();
    double totalMoney1 = t1.getTotalMoney(list);
    double discountMoney1 = t1.getDiscountMoney(totalMoney1);
    System.out.println("美团需要付钱总数：" + (totalMoney1 - discountMoney1) + ",共优惠了：" + discountMoney1);
    Takeaway t2 = new Eleme();
    double totalMoney2 = t2.getTotalMoney(list);
    double discountMoney2 = t2.getDiscountMoney(totalMoney1);
    System.out.println("饿了么需要付钱总数：" + (totalMoney2 - discountMoney2) + ",共优惠了：" + discountMoney2);
}

运行截图

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