Question

我需要创建一个程序来计算用户输入的测试分数的平均值。这实际上是我第二次有人要求制作这个节目。但是这次分配要求我在用户输入小于0或大于100的testscore时抛出IllgalArgumentException。问题是即使测试分数在0到100之间，无论什么测试分数，程序都会崩溃，并且会出现IllegalArgumentException。。不知道我做错了什么想法这里没有例外的预期输出

预期输出

Enter number of test scores:5
Enter test score 1:70
Enter test score 2:65
Enter test score 3:94
Enter test score 4:55
Enter test score 5:90
74.8

和我的代码

public static void main(String[] args) throws IllegalArgumentException 
{
    Scanner input = new Scanner (System.in);
    int numTests = 0;
    int [] grade = new int [numTests];
    double average;
    double totalGrades = 0;

    System.out.print("Enter number of test scores:");
    numTests = input.nextInt();
    grade = new int[numTests];

    for (int index = 0; index < grade.length; index++)
    {
        System.out.print("Enter test score "  + (index + 1) + ":");
        grade[index] = input.nextInt();


            if(grade[index] < 0 || grade[index] > 100);
            {
                throw new IllegalArgumentException();

            }        
    }

    for (int i = 0; i < grade.length; i++)
    {
        totalGrades += grade[i];
    }

    average = totalGrades / grade.length;

    System.out.println(average);

}

private static class IllegalArgumentException extends Exception
{
    public IllegalArgumentException()
    {
        super("Test scores must have a value  less than  100 and greater than  0.");
    }

    public IllegalArgumentException(int value)
    {
        super("Invalid Test Score: " + value);
    }
}

Answer 1

if(grade[index] < 0 || grade[index] > 100);
{
  throw new IllegalArgumentException();
}

;行末尾的if表示无条件执行throw，因为它不在条件块中。

您的代码（有效）与：

相同

if(grade[index] < 0 || grade[index] > 100) { /* do nothing */ }
throw new IllegalArgumentException();

删除;。

为什么我的每个输入都会收到IllegalArgumentException？

1 个答案: