java.lang.ArrayIndexOutOfBoundsException：10

Question

我是新手，我尝试编写一个程序来计算数组中10个数字的偏差，这是我创建的代码：

package week10;

import java.util.Scanner;

public class deviation {
    public static void main(String[]args) {

        Scanner input = new Scanner(System.in);
        double testScores[] = new double [10];
        double sum = 0;

        int count = 0;
        int count2 = 0;
        int count3 = 0;

        double inputDouble = 0;
        int arrayIndex = 0;

        //GET INPUT TEST SCORES
        while(inputDouble >= 0) {
            System.out.print("Enter Score: ");

            inputDouble = input.nextDouble();
            if(inputDouble >= 0)
            {
                testScores[arrayIndex] = inputDouble;
                sum += inputDouble;
            }
            arrayIndex++;
        }

        if(arrayIndex < testScores.length)
        {
            for (int x = arrayIndex-1; x <= testScores.length-1; x++)
            {
                testScores[x] = -1;
            }
        }

        //GET NEW ARRAY WITH ONLY VALID SCORES
        double[] validScores = GetValidScores(testScores, arrayIndex-1);

        System.out.println(" The mean is: " + mean(validScores));
        System.out.println(" The standard deviation is: " + deviation(validScores));            
    }

    private static double[] GetValidScores(double[] inputArray, int validScoreCount) {
        double[] newScores = new double[validScoreCount];
        for(int z = 0; z < validScoreCount; z++)
        {
            newScores[z] = inputArray[z];
        }
        return newScores;
    }

    public static double deviation(double[] values) {
        double sum = 0.00;

        double theMean = mean(values);

        for(int i =0; i < values.length; i++) {
            double currentCalc = values[i] - theMean;
            sum += Math.pow(currentCalc, 2);
        }

        sum = sum / (values.length -1);

        sum = Math.sqrt(sum);

        return sum;
    }

    public static double mean(double[] values)
    {
        double sum = 0.00;

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

        return sum / values.length;
    }

}

输出：

Enter Score: 25
Enter Score: 25
Enter Score: 25
Enter Score: 25
Enter Score: 25
Enter Score: 25
Enter Score: 25
Enter Score: 25
Enter Score: 25
Enter Score: 25
Enter Score: 25

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 1 at week10.deviation.main(deviation.java:26)"

我知道数组是10，但它以0开头，所以这就是我选择命令数组-1的原因，你能告诉我或者说明我做错了吗？

Answer 1

你有一个包含10个元素的数组，并在循环中请求下一个元素，直到用户输入负值。由于用户总是输入25，因此循环永远不会停止，直到它到达第11个元素。访问10个元素数组的第11个元素（在索引10处）会抛出您看到的异常。

Answer 2

如果您想要准确读取10个数字，请更改此处的阅读输入部分

//GET INPUT TEST SCORES
for(int i=0;i<10;i++)    
    System.out.print("Enter Score: ");

    inputDouble = input.nextDouble();
    testScores[i] = inputDouble;
    sum += inputDouble;
}