超出范围的异常乘法数组

Question

据我所知，这个程序是正确完成的。但是，鉴于例外它似乎没有。我要制作2个长度为x的数组（用户输入），用户输入元素。完成。接下来，将每个元素乘以另一个数组中的相应元素，并添加总和。

Ex，array1 [0] * array2 [0] + array1 [1] * array2 [1] ...

精确错误是：线程“main”中的异常java.lang.ArrayIndexOutOfBoundsException：

我已经做了很多不同的循环，下面的最后一个循环，我有额外的间隔来识别是我认为最接近正确但不是。我非常感谢你的建议，谢谢你。

   System.out.println("This program will multiply 2 one dimension arrays of any length. \n The length and contents of the array is entered from the keyboard.");
    System.out.println("Enther the data for the first array. ");

    System.out.println("Enther the length of the array (remember arrays being counting at 0, not 1:");

    int a = 0;
    Scanner keyboard = new Scanner(System.in);
    a = keyboard.nextInt();
    int[] firstArrayLength = new int[a];
    System.out.println("Enter the elements of the first array(remember arrays begin counting at 0, not 1");
    double arrayElements = 0;
    for (int elements = 0; elements <= firstArrayLength.length; elements++) {

        arrayElements = keyboard.nextInt();
    }

    System.out.println("Enter the data for the second array. ");
    System.out.println("Enter the elements of the second  array(remember arrays begin counting at 0, not 1");
    int[] secondArrayLength = new int[a];

    double secondArrayElements = 0;
    for (int elements = 0; elements <= secondArrayLength.length; elements++) {

        secondArrayElements = keyboard.nextInt();
    }
    double [] thirdArray = new double [a];





    for (int i =0; i <=firstArrayLength.length; i++)
       {
        thirdArray[a] = firstArrayLength[i]*secondArrayLength[i];
        }
    System.out.println(thirdArray);
        }

Answer 1

访问de array时，将<=符号更改为<。例如：

for (int elements = 0; elements < firstArrayLength.length; elements++)
...

请记住，如果length为4，您可以访问以下元素：

array[0], array[1], array[2], array[3] // 4 elements

array[4]不存在，导致IndexOutOfBounds例外。

修改

奇怪的输出[I@756a7c99（例如）是因为您将数组打印为：

int a[] = new int[4];
System.out.println(a);

相反，您可能希望打印该数组的元素：

int a[] = new int[4];
for (int i = 0; i < 4; i++) {
    System.out.println(a[i]);
}

修改2

public static void main(String[] args) {
    System.out
            .println("This program will multiply 2 one dimension arrays of any length. \n The length and contents of the array is entered from the keyboard.");
    System.out.println("Enther the data for the first array. ");

    System.out
            .println("Enther the length of the array (remember arrays being counting at 0, not 1:");

    int a = 0;
    Scanner keyboard = new Scanner(System.in);
    a = keyboard.nextInt();
    int[] firstArray = new int[a];
    System.out
            .println("Enter the elements of the first array(remember arrays begin counting at 0, not 1");
    for (int elements = 0; elements < firstArray.length; elements++) {

        firstArray[elements] = keyboard.nextInt();
    }

    System.out.println("Enter the data for the second array. ");
    System.out
            .println("Enter the elements of the second  array(remember arrays begin counting at 0, not 1");
    int[] secondArray = new int[a];

    for (int elements = 0; elements < secondArray.length; elements++) {

        secondArray[elements] = keyboard.nextInt();
    }
    double[] thirdArray = new double[a];

    for (int i = 0; i < firstArray.length; i++) {
        thirdArray[i] = firstArray[i]*secondArray[i];
    }

    for (int i = 0; i < thirdArray.length; i++)
        System.out.println(thirdArray[i]);
}

Answer 2

elements <= firstArrayLength.length ==＆gt; elements < firstArrayLength.length

arrayElements = keyboard.nextInt(); ==＆gt;＆gt; firstArrayLength[elements] = keyboard.nextInt();

secondArrayElements = keyboard.nextInt(); ==＆gt;＆gt; secondArrayLength[elements] = keyboard.nextInt();