Copy two 2D arrays to another 2D array

I have another Java question:)

I've read the this thread and it clearly explains it, but I have two 2D arrays I want to copy

I understand this code

int[] array1and2 = new int[array1.length + array2.length];
System.arraycopy(array1,array1and2,array1.length);
System.arraycopy(array2,array1.length,array2.length);

But my question is, how to merge it with two arrays and where

int a1[][] = new int [3][3];
int b1[][] = new int [3][3];
int c1[][] = new int [3][6];

Where C1 is the combination of the above arrays?

Solution

Use the task solution you mentioned in the problem Example:

import java.util.Arrays;

public class ArrayProgram {

    public static void main(String[] args) {
        int[][] array1 = { { 1,2,3 },{ 1,3 } };
        int[][] array2 = { { 4,5,6 },{ 7,8,9 },{ 0,1,2 } };
        int[][] result = ArrayCopier.joinSecondDimension(array1,array2);
        for (int[] array : result) {
            System.out.println(Arrays.toString(array));
        }
    }
}

class ArrayCopier {

    public static int[][] joinSecondDimension(int[][] array1,int[][] array2) {
        int[][] array1and2 = new int[array1.length][];
        for (int index = 0; index < array1.length; index++) {
            array1and2[index] = join(array1[index],array2[index]);
        }
        return array1and2;
    }

    public static int[] join(int[] array1,int[] array2) {
        int[] array1and2 = new int[array1.length + array2.length];
        System.arraycopy(array1,array1.length);
        System.arraycopy(array2,array2.length);
        return array1and2;
    }
}

Print:

[1,3,4,6]
[1,7,9]
[1,2]

Edit the implementation of any parameter number (variable length argument lists):

import java.util.Arrays;

public class ArrayProgram {

    public static void main(String[] args) {
        int[][] array1 = { { 1,{ 4,9 } };
        int[][] array2 = { { 1,9 } };
        int[][] array3 = { { 1,9 } };
        test(array1);
        test(array1,array2);
        test(array1,array2,array3);
    }

    private static void test(int[][]... arrays) {
        int[][] result = ArrayCopier.joinSecondDimension(arrays);
        for (int[] array : result) {
            System.out.println(Arrays.toString(array));
        }
        System.out.println();
    }
}

class ArrayCopier {

    public static int[][] joinSecondDimension(int[][]... arrays) {
        int firstArrayLength = arrays[0].length;
        int[][] result = new int[firstArrayLength][];
        for (int index = 0; index < firstArrayLength; index++) {
            result[index] = join(getSecondDimArrays(index,arrays));
        }
        return result;
    }

    public static int[] join(int[]... arrays) {
        int[] result = new int[getTotalLength(arrays)];
        int destPos = 0;
        for (int[] array : arrays) {
            System.arraycopy(array,result,destPos,array.length);
            destPos += array.length;
        }
        return result;
    }

    private static int getTotalLength(int[]... arrays) {
        int length = 0;
        for (int[] array : arrays) {
            length += array.length;
        }
        return length;
    }

    private static int[][] getSecondDimArrays(int index,int[][]... arrays) {
        int[][] result = new int[arrays.length][];
        int resultIndex = 0;
        for (int[][] array : arrays) {
            result[resultIndex++] = array[index];
        }
        return result;
    }
}

Print:

[1,3]
[4,6]
[7,9]

[1,6,9,9]