How to Reverse an Array in Java Using for Loop

Learn how to reverse an array in Java using a for loop. here we are traverse an array from the last index to the first and display elements in reverse order.

Code Explanation (Step-by-Step)

  • Creates a Scanner object to read user input from the keyboard.
  • Creates an integer array with a maximum size of 20 elements.
  • Uses the sc.nextInt() method to read the number of elements entered by the user and stores it in the variable n.
  • Starts a for loop to read and store the array elements.
  • Reads each element entered by the user and stores it in the array at index i.
  • Prints a heading before displaying the array in reverse order.
  • Starts a loop from the last index of the array and moves backward to the first index.
  • Prints each array element in reverse order.
				
					import java.util.Scanner;

public class ReverseArray {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int arr[] = new int[20];

        System.out.println("Enter the number of elements:- ");
        int n = sc.nextInt();

        System.out.println("Enter the elements:- ");
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
        }

        System.out.print("Array in reverse order :- ");
        for (int j = (n - 1); j >= 0; j--) {
            System.out.print(arr[j] + " ");
        }

        sc.close();
    }
}

Output :-
Enter the number of elements:-
4
Enter the elements:-
11
12
13
14
Array in reverse order :- 14 13 12 11

Java Program to Reverse an Array Without Using Another Array

				
					import java.util.Scanner;

public class ReverseArrayInPlace {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int arr[] = new int[20];

        System.out.println("Enter the number of elements:");
        int n = sc.nextInt();

        System.out.println("Enter the elements:");
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
        }

        int start = 0;
        int end = n - 1;

        while (start < end) {
            int temp = arr[start];
            arr[start] = arr[end];
            arr[end] = temp;

            start++;
            end--;
        }

        System.out.println("Array after reversing:");
        for (int i = 0; i < n; i++) {
            System.out.print(arr[i] + " ");
        }

        sc.close();
    }
}

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