Question

我已经完成了这项作业，我将要扔掉这台笔记本电脑。下面的代码运行，但是当我在MindTap中对其进行测试时，我得到了最下面的消息。我不知道我在做什么错，或者为什么它说错了。

任务：为照相簿商店编写三种重载的computeBill方法：

computeBill收到一个参数时，它表示订购的一本相册的价格。加上8％的税，并返还应付总额。当computeBill收到两个参数时，它们代表一本相簿的价格和订购的数量。将两个值相乘，加上8％的税，然后返回应付总额。当calculateBill收到三个参数时，它们代表一本相簿的价格，订购的数量和优惠券价值。将数量和价格相乘，将结果乘以票面价值，然后加8％的税金，并返还应付总额。

我的编码：在此处输入代码公共类帐单{

public static void main(String args[]){
   double yourTotal;
    yourTotal = computeBill(31.00);
    displayTotal (yourTotal);
    yourTotal = computeBill (31, 2);
    displayTotal(yourTotal);
    yourTotal = computeBill(31, 2, .2); 
    displayTotal (yourTotal);
 }
 public static double computeBill (double price) 
{double total = price * 1.08;
 System.out.println ("You ordered 1 photobook for $" + price);
 System.out.println("Plus sales tax 8%");
 return total;}

public static double computeBill (double price, int qty) {
double subtotal = price * qty;
double total = subtotal * 1.08;
 System.out.println ("You ordered" + qty + " photobook(s) for $" + price);
 System.out.println("Subtotal =" + subtotal);
System.out.println("Plus sales tax 8%");
return total;
 }

public static double computeBill (double price, int qty, double discount) {
double subtotal = price * qty;
 subtotal = subtotal - (subtotal * discount);    
 double total = subtotal * 1.08;
  System.out.println ("You ordered " + qty + " photobook(s) for $" + price);
  System.out.println("Subtotal = " + subtotal);
  System.out.println("Less your " + (discount * 100) + "% discount"); 
System.out.println("Plus sales tax 8%");   
return total;
}
public static void displayTotal (double total){
    System.out.println("Total: $" + total);
  }
  }

结果当我测试时，MindTap给了我：建立状态建立成功测试输出您以$ 31.0的价格订购了2本相册小计= 62.0 加上营业税8％ [FAILED]：unitTest（CodevolveTest12f618f0）：空假测试内容 Billing tester30 = new Billing（）;

@Test
public void unitTest() {
assertTrue(tester30.computeBill(31, 2) == 66.96);

}

请帮助我。我被卡住了！！！

Answer 1

您需要限制小数点后的位数，以使比较变得合乎逻辑：

public static double computeBill (double price, int qty) {
        double subtotal = price * qty;
        double total = subtotal * 1.08;
        System.out.println ("You ordered" + qty + " photobook(s) for $" + price);
        System.out.println("Subtotal =" + subtotal);
        System.out.println("Plus sales tax 8%");

        // need to limit to two digit after decimal
        return Double.parseDouble(new DecimalFormat("##.##").format(total));
}

因此，您进行测试：

@Test
public void unitTest() {
     assertTrue(tester30.computeBill(31, 2) == 66.96); // comparing two digits after decimal 
}

代码运行，但它说的是错误的答案，并且无法继续处理我不理解的消息

1 个答案: