How to find 3D Array index values

Question

I konw the three dimensional (3D) array can be thought of as an array of arrays of arrays. And i have int[3][4][2] 3Darray i can initialize using for loop

Example

 public class JavaProgram
    {
       public static void main(String args[])
       {
          int arr[][][] = new int[3][4][2];
          int i, j, k, num=1;

          for(i=0; i<3; i++)
          {
              for(j=0; j<4; j++)
              {
                  for(k=0; k<2; k++)
                  {
                      arr[i][j][k] = num;
                      num++;
                  }
              }
          }

           for(i=0; i<3; i++)
          {
              for(j=0; j<4; j++)
              {
                  for(k=0; k<2; k++)
                  {
                      System.out.print("arr[" +i+ "][" +j+ "][" +k+ "] = " +arr[i][j][k]+ "\t");
                  }
                  System.out.println();
              }
              System.out.println();
          }
       }
    }

output look like

And i have 3d Array like

int[][][] matrix = {{{1, 2, 3},{4, 5, 6}}, {
            {10, 20, 30},{40, 50, 60}}};

And i not able to find out position all elements like matrix[0][0][0]=1. What is index value of other elements. please any one help me to find

Answer 1

Just iterate over the array as you did in your example but use the length -attribute:

    int[][][] matrix = { { { 1, 2, 3 }, { 4, 5, 6 } }, { { 10, 20, 30 }, { 40, 50, 60 } } };

    for (int i = 0; i < matrix.length; i++)
    {
        for (int j = 0; j < matrix[i].length; j++)
        {
            for (int k = 0; k < matrix[i][j].length; k++)
            {
                System.out.print("matrix[" + i + "][" + j + "][" + k + "] = " + matrix[i][j][k] + "\t");
            }
            System.out.println();
        }
        System.out.println();
    }

If you want to access a specific element, you can also use length to find out which range is valid. You can find more information here .

Answer 2

This is your array:

int[][][] matrix = { //-------------------Start of your first array contains two elements as 2D array.
                      { //----------First element of First array, which contains two 1D array.
                        { 1, 2, 3 }, //First element of 2D array.
                        { 4, 5, 6 }  //Second element of 2D array.
                      }, //First element of 3D array ends here.
                      { // Second element of 3D array contains 2 1D array.
                        { 10, 20, 30 },
                        { 40, 50, 60 }
                      } 
                    };

Now if you want to get position of any number, Take example I want the position of 20:

1. 20 number present in the second 2D array of 3D array. So matrix[1].
2. 20 number present in first 1D array of 2D array So. matrix[1][0].
3. 20 number present at second position of 1D array. So matrix[1][0][1].

Now if you want to go with the complete loop. use length to find out the array length which will act as your index.

for (int i = 0; i < matrix.length; i++)
    {
        for (int j = 0; j < matrix[i].length; j++)
        {
            for (int k = 0; k < matrix[i][j].length; k++)
            {
                System.out.print("[" + i + "][" + j + "][" + k + "] = " + matrix[i][j][k] + "\t");
            }
            System.out.println();
        }
        System.out.println();
    }