Program to Reverse an array

Solution 1 - Revere array in Place (not recommended)

package interview;

import java.util.Arrays;
import java.util.List;

public class Reverse_Array {

public static void main(String[] args)
{
   int[] arr = {1,2,3,4,5,6,7,8,9,10};
   System.out.println("Before : "+Arrays.toString(arr));
   /*List<int[]> l = Arrays.asList(arr);
   System.out.println(l.toArray());*/
   for(int i =0 , j = arr.length-1; i<j; i++,j--)
   {
   int temp = arr[i];
   arr[i] = arr[j];
   arr[j] = temp;
 
   }
   System.out.println("After : "+Arrays.toString(arr));
 
 
}

}

Solution 2 - Revere array in Place (for interview)

package phase_one;

import java.util.Arrays;

public class ReverseArray_Using_ForLoop 

{

public static void main(String[] args) 

{

  int[] arr = new int[] {7,84,3,9,11,6};

  System.out.println("Before: "+Arrays.toString(arr));

  for(int i= 0;i<arr.length/2;i++)

  {

  int temp = arr[i];

  arr[i] =   arr[arr.length-i-1];

  arr[arr.length-i-1] = temp;

  }

  System.out.println("After: "+Arrays.toString(arr));

}

}

Solution 3 - Revere array Using Collections

package phase_one;

import java.util.Arrays;

import java.util.Collections;

import java.util.List;

public class ReverseArray_Using_ArrayList {

public static void main(String[] args) 

{

String[] arr = {"apple", "tree", "play"};

      System.out.println("before: " + Arrays.toString(arr) );

      List<String> listOfProducts = Arrays.asList(arr);      

      Collections.reverse(listOfProducts);

      String[] reversed = listOfProducts.toArray(arr);

      System.out.println("after: " + Arrays.toString(reversed) );

      

      System.out.println("**************************************");

     

      Integer[] arr2 = new Integer[] {1,2,3,4,5};

     // List<Integer> list = Arrays.asList(arr2);       

     System.out.println(Arrays.toString(arr2));

     List<Integer> li = Arrays.asList(arr2);  //--array to List

     Collections.reverse(li); // reverse List

     Integer[] rev = li.toArray(arr2);

     System.out.println(Arrays.toString(rev));

     

 

}

}