java - 更改程序无法使用 1.16 美元

Question

该程序除了 1.16 美元外都进行了更改，为什么处理不正确？

public class Change {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.println("Enter Change: ");
        double change = in.nextDouble()*100;
        int dollars = Math.round((int)change/100);
        change=change%100;
        int quarters = Math.round((int)change/25);
        change=change%25;
        int dimes = Math.round((int)change/10);
        change=change%10;
        int nickels = Math.round((int)change/5);
        change=change%5;
        int pennies = Math.round((int)change/1);

        System.out.println("Dollars: " + dollars);
        System.out.println("Quarters: " + quarters);
        System.out.println("Dimes: " + dimes);
        System.out.println("Nickels: " + nickels);
        System.out.println("Pennies: " + pennies);
    }
}

我认为这是一个截断问题，因为当我在下面的代码中使用 .9 时它可以工作:

int pennies = Math.round((int)change/.9);

Answer 1

问题是变化是双重的。当我运行它时，我在便士声明之前打印了零钱，这就是打印的内容:0.9999999999999858。当它转换为 int 时，它会变成 0。所以 0/1 是 0。不要对 double 使用模数除法。当您输入 1.16 时，它将返回 1.1599999999999999999999999999999。尝试将输入向上舍入。

        Scanner in = new Scanner(System.in);
        System.out.println("Enter Change: ");
        int change = (int)(Math.ceil(in.nextDouble()*100));
        int dollars = Math.round((int)change/100);
        change=change%100;
        int quarters = Math.round((int)change/25);
        change=change%25;
        int dimes = Math.round((int)change/10);
        change=change%10;
        int nickels = Math.round((int)change/5);
        change=change%5;
        int pennies = Math.round((int)change/1);

        System.out.println("Dollars: " + dollars);
        System.out.println("Quarters: " + quarters);
        System.out.println("Dimes: " + dimes);
        System.out.println("Nickels: " + nickels);
        System.out.println("Pennies: " + pennies);

此代码有效。