为什么最近一次美元变动计算会出错

Question

为什么最后一个计算会打印出错误的计算。这是我的代码：

System.out.print（“输入总成本：”）;

double totalCost = input.nextDouble();
        System.out.print("The Customer has paid: ");
        double customerAmount = input.nextDouble();

        //Calculations
        double changeOwed = customerAmount - totalCost;
        System.out.println("Change owed: $"+(int)changeOwed);

        int amountFifty = (int)changeOwed/50;
        System.out.println("How many $50 notes = " +amountFifty);

        int takeAway = (int)changeOwed - (amountFifty * 50);

        int amount20 = takeAway / 20;
        System.out.println("How many $20 notes = " +amount20);

        int amount10 = (takeAway - amount20*20) / 10;
        System.out.println("How many $10 notes = " +amount10);
    enter code here
        int amount5 = (takeAway - amount10*10) / 5;
        System.out.println("How many $5 notes = " +amount5);

        int amount2 = (takeAway - amount5*5) / 2;
        System.out.println("How many $2 notes = " +amount2);

        int amount1 = (takeAway - amount2*2) /1;
        System.out.printl

n（“多少个$ 1钞票=” + amount1）;

Answer 1

您没有正确跟踪沿途发布的更改。

int takeAway = (int)changeOwed - (amountFifty * 50);

上面的行正确地确定了所需的50美元面额的钞票后剩余的东西。这意味着：

int amount20 = takeAway / 20;
int amount10 = (takeAway - amount20*20) / 10;

正确计算10美元和20美元的钞票数。

int amount5 = (takeAway - amount10*10) / 5;

是不正确的，因为您没有减去20美元面额的钞票。您在计算$ 2时也犯了类似的错误，即。您不需支付$ 20和$ 10的费用。 $ 1的错误复合。