Home / Array / Java / Recursion / Java Program to Display Array Elements in Reverse Order

Java Program to Display Array Elements in Reverse Order

in , ,
Array elements in reverse order

Java programs to display array elements in reverse order have been shown here. Both of the iterative and recursive approaches have been covered. The algorithm, pseudocode and time complexity of the programs have also been given.


Example:

Given array A[] = {5, 10, 15, 25, 30}

Elements of A[] in reverse order = {30, 25, 15, 10, 5}







1. Algorithm to display array elements in reverse order


1. Take input of an array $A[~]$ and the size $n$

2. Set $i = n - 1$

3. For each $i$ from $n - 1$ to $0$, dislay $A[i]$




2. Pseudocode to display array elements in reverse order


Input: An array $A[~]$ and size of array $n$

Output: Array elements in reverse order.

1. Procedure reverse($A[~]$, $n$):

2. Repeat for $i \in [n-1, 0]$:

3. Print $A[i]$

4. End Procedure





3. Time complexity to display array elements in reverse order


Time Complexity: O(n)

Here $n$ is the number of elements in the array.




4. Program & output to display array elements in reverse order




4.1. Java Program & output to display array elements in reverse order using iterative approach

Code has been copied
/***************************************
	  alphabetacoder.com
Java program to print elements of array 
in reverse order using iteration
****************************************/

class Main {
    public static void main(String args[]) {
        // declare an array
        int[] arr = {10, 20, 30, 40, 50, 60, 70, 80};
        // declare variables
        int i, length;

        // calculate size of array
        length = arr.length;

        // display the array
        System.out.print("Original array: ");
        for (i = 0; i < length; i++)
            System.out.print(arr[i] + " ");

        // display array elements in reverse order
        System.out.print("\nReverse array : ");
        for (i = length - 1; i >= 0; i--)
            System.out.print(arr[i] + " ");
    }
}

Output

Original array: 10 20 30 40 50 60 70 80

Reverse array : 80 70 60 50 40 30 20 10




4.2. Java Program to display array elements in reverse order using recursion

Code has been copied
/***************************************
	   alphabetacoder.com
Java program to print elements of array 
in reverse order using recursion
****************************************/

class Main {
    // display elements of array in reverse
    // order function takes an array arr and 
    // an index i as arguments
    public static void reverse(int arr[], int i) {
        // exit condition of recursive call 
        if (i < 0)
            return;
        // print current element
        System.out.print(arr[i] + " ");
        // call function
        reverse(arr, i - 1);
    }

    public static void main(String args[]) {
        // declare an array
        int[] arr = {10, 20, 30, 40, 50, 60, 70, 80};
        // declare variables
        int i, length;

        // calculate size of array
        length = arr.length;

        // display the array
        System.out.print("Original array: ");
        for (i = 0; i < length; i++)
            System.out.print(arr[i] + " ");

        // display array elements in reverse
        // order using recursive function reverse()
        // pass array arr and last index of array as
        // arguments
        System.out.print("\nReverse array : ");
        reverse(arr, length - 1);
    }
}



Labels: , ,