Traverse 2d Array Java

Traverse 2d Array Java | A 2d array is a multidimensional array. It can be also said that it is an array of arrays. We store the elements in the multidimensional array in rows and columns in the form of a matrix. Example for 2d array:-
int array[ ][ ] = {{1,2,3},{3,4,5},{6,7,8}};

This initializes the array directly, to take elements from the user we can declare it as follows:- int arr[ ][ ] = new int[ ][ ];

To access the array elements we need to use a loop. Let us demonstrate the iterating through a 2d array Java.

Iterating Through a 2d Array Java

public class Main {
  public static void main(String[] args) {
    int[][] elements = 
           { 
             { 1, 2, 3 }, 
             { 4, 5, 6 }, 
             { 7, 8, 9 } 
           };

    System.out.println("The array elements are :");
    for (int i = 0; i < elements.length; i++) {
      for (int j = 0; j < elements[i].length; j++) {
        System.out.print(elements[i][j] + "\t");
      }
      System.out.println("");
    }
  }
}

Output:-

The array elements are :
1 2 3
4 5 6
7 8 9

The Explanation of the above code of traversing 2d array Java goes as follows:- Here we have used the array of integers and initialized it directly. By using the for loops we print the array elements.

As this is a 2d array, therefore to access the elements we need two for loops. The loop will start from 0 to the length of the array. Also see:- How to find the length of the 2D array in Java

The elements.length gives the length of the row in the 2d array and elements[i].length gives the length of the i^th column in the given 2d array. To access the elements we have to use elements[i][j].

Traverse 2d Array Java using Enhanced For Loop

There is a another way of using for loop we call this as for each loop. Let us see the demonstration of the for each loop.

public class Main {
  public static void main(String[] args) {
    int[][] elements = 
            { 
              { 1, 1, 1 }, 
              { 2, 2, 2 }, 
              { 3, 3, 3 } 
            };

    System.out.println("Using Enhanced for loop:");
    for (int[] eachRow : elements) {
      for (int j : eachRow) {
        System.out.print(j + "\t");
      }
      System.out.println("");
    }
  }
}

Output:

Using Enhanced for loop:
1 1 1
2 2 2
3 3 3

Traversing 2d Array Java by Taking User Input

Now let us see how to traverse a 2d array in Java after taking input from the end-user.

import java.util.Scanner;

public class Main {
   public static void main(String[] args) {
      Scanner scan = new Scanner(System.in);
      int[][] elements = new int[2][2];
      System.out.println("Enter the elements in 2D array (2x2): ");
      for (int i = 0; i < elements.length; i++) {
         for (int j = 0; j < elements[i].length; j++) {
            elements[i][j] = scan.nextInt();

         }
      }

      System.out.println("The array Elements are :");
      for (int i = 0; i < elements.length; i++) {
         for (int j = 0; j < elements[i].length; j++) {
            System.out.print(elements[i][j] + "\t");
         }
         System.out.println("");
      }
      scan.close();
   }
}

Output:

Enter the elements in 2D array (2×2):
1 2
3 4
The array Elements are :
1 2
3 4

Also see:- Sum of matrix elements in Java, Sum of Diagonal Elements of Matrix

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