Question

此代码的目标是将单维数组乘以2维数组。下面的产品数组是我试图获取并打印

我面临的错误是方法 outputArray ，

示例输出：

arrayOne[] = 2,4
arrayTwo[][] = 2,4,6
               8,10,12
productArray = (2*2 + 4*8) , (2*4 + 4*10) , (2*6 + 4*12)

    public static void main(String[] args) {
        // TODO code application logic here   
        description();
        int arrayLength = getLength();
        double[] arrayOne = getArrayOne(arrayLength);
        int numCol = getNumColumn();
        int rows = numCol;
        double[][] arrayTwo = getArrayTwo(rows, numCol);
        outputArray(arrayOne, arrayTwo, rows, numCol);
    }


    public static int getLength() {
        Scanner input = new Scanner(System.in);
        System.out.println("Enter the length of the first array");
        int length = input.nextInt();
        return length;
    }


    public static double[] getArrayOne(int length) {
        Scanner input = new Scanner(System.in);
        double array[] = new double[length];
        System.out.println("Please enter the contents of the first array: ");
        for (int i = 0; i < length; ++i) {
            array[i] = input.nextDouble();
        }
        return array;
    }


    public static int getNumColumn() {
        Scanner input = new Scanner(System.in);
        int numcolumn;
        System.out.println("Enter the number of columns of the 2D array: ");
        int numColumn = input.nextInt();
        return numColumn;
    }


    public static double[][] getArrayTwo(int rows, int columns) {
        Scanner input = new Scanner(System.in);
        System.out.println("Please enter the contents of the second array: ");
        double array[][] = new double[rows][columns];
        for (int i = 0; i < rows; ++i) {
            for (int j = 0; j < columns; ++j) {
                array[i][j] = input.nextDouble();
            }
        }
        return array;    
    }


    public static void outputArray (double[] arrayOne, double[][] arrayTwo, int rows, int column) {
        double sum = 0;
        Double productArray[] = new Double[column];
        for (int i = 0; i < rows; i++){
            sum += arrayOne[i] * arrayTwo[i][0];
            productArray[arrayOne.length] = sum;
        }
        for (int i = 0; i < productArray.length; i++){
            System.out.println(" " + productArray[i]);
        }            
    }


    public static void description() {
        System.out.println("This program will multiply 2 one dimension arrays of any length. The length and the contents of the arrays is entered from the keyboard.");
    }

Answer 1

在outputArray()中，你以错误的方式嵌套循环;你应该在你的列循环中有行循环。它应该是：

    for (int k = 0; k < column; k++) {

        int sum = 0;
        for (int j = 0; j < rows; j++) {
            sum += arrayTwo[j][k] * arrayOne[j];
        }

        productArray[k] = sum;

    }

打印出数组[36.0,48.0,60.0]

用Java中的2D数组乘以数组

1 个答案: