java loop array backwards code example

Example 1: Reverse an array in java using for loop

// Reverse an array in java using for loop
public class ReverseArrayUsingForLoop 
{
   public static void main(String[] args) 
   {
      int[] arrNumbers = new int[]{2, 4, 6, 8, 10};  
      System.out.println("Given array: ");  
      for(int a = 0; a < arrNumbers.length; a++)
      {
         System.out.print(arrNumbers[a] + " ");
      }
      System.out.println("Reverse array: ");
      // looping array in reverse order
      for(int a = arrNumbers.length - 1; a >= 0; a--) 
      {  
         System.out.print(arrNumbers[a] + " ");  
      }
   }
}

Example 2: reverse an array in java using while loop

import java.util.Scanner;
public class Example
{
   public static void main(String args[])
   {
	int counter, i=0, j=0, temp;
	int number[] = new int[100];
	Scanner scanner = new Scanner(System.in);
	System.out.print("How many elements you want to enter: ");
	counter = scanner.nextInt();

	/* This loop stores all the elements that we enter in an 
	 * the array number. First element is at number[0], second at 
	 * number[1] and so on
	 */
	for(i=0; i<counter; i++)
	{
	    System.out.print("Enter Array Element"+(i+1)+": ");
	    number[i] = scanner.nextInt();
	}

	/* Here we are writing the logic to swap first element with
	 * last element, second last element with second element and
	 * so on. On the first iteration of while loop i is the index 
	 * of first element and j is the index of last. On the second
	 * iteration i is the index of second and j is the index of 
	 * second last.
	 */
	j = i - 1;     
	i = 0;         
	scanner.close();
	while(i<j)
	{
  	   temp = number[i];
	   number[i] = number[j];
	   number[j] = temp;
	   i++;
	   j--;
	}

	System.out.print("Reversed array: ");
	for(i=0; i<counter; i++)
	{
	   System.out.print(number[i]+ "  ");
	}       
   }
}