Reverse the array elements in java.

Method 1 -> using extra array 

import java.util.Scanner;

public class Main

{

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

System.out.println("enter size=");

int n=sc.nextInt();

int[] arr=new int[n];

int[] rev=new int[n];

int i=0;

System.out.println("enter elements=");

for(i=0; i<n; i++){

      arr[i]=sc.nextInt();

}

i=0;

for(int j=n-1; j>=0; j--){

      rev[i++]=arr[j];

}

System.out.println("array is=");

      for(int ele : arr)

      System.out.print(ele+" ");

      System.out.println("\nreverse array is=");

      for(int ele : rev)

      System.out.print(ele+" ");

}

}

Method 2 -> without using extra array [ two pointer technique ]  

import java.util.Scanner;

public class Main

{

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

System.out.print("enter array size=");

int n=sc.nextInt();

int[] arr=new int[n];

System.out.println("enter elements in array=");

for(int i=0; i<n; i++){

      arr[i]=sc.nextInt();

}

System.out.println("array is=");

for(int ele: arr){

      System.out.print(ele+" ");

}

int i=0,j=n-1;

while(i<=j){

      swap(arr,i,j);

      i++;

      j--;

}

System.out.println("\nreverse array is=");

for(int ele: arr){

      System.out.print(ele+" ");

}

}

public static void swap(int[] arr,int i, int j){

     int temp= arr[i];

     arr[i]=arr[j];

     arr[j]=temp;

}

}

Method 3 -> without using extra array [one pointer technique ]  

import java.util.Scanner;

public class Main

{

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

System.out.println("enter size=");

int n=sc.nextInt();

int[] arr=new int[n];

System.out.println("enter elements=");

for(int i=0; i<n; i++){

      arr[i]=sc.nextInt();

}

System.out.println("\narray is=");

      for(int ele : arr)

      System.out.print(ele+" ");

for(int j=0; j<n/2; j++){

     int t=arr[j];

     arr[j]=arr[n-1-j];

     arr[n-1-j]=t;

}

      System.out.println("\nreverse array is=");

      for(int ele : arr)

      System.out.print(ele+" ");

}

}