Reverse an array in Java

 Write a program to reverse an array or string in java.👇👇👇

input - 

int arr[] = {2,3,4,5,6}

output - 

int arr[] = {6,5,4,3,2}

Here we have two approaches to reverse an array.

1- Iterative

2- Recursive

Iterative - 

In the Iterative way, we go from start to end one by one and swap arr[start] with arr[end],

and after that do start++ and end--;

we have to repeat this till start<end;

*********Code*****************

package javaoneworld.learndsa.problems;

public class JavaOneWorldReverse {

    public static void main(String[] args) {

        int arrToReverse[] = {2,3,4,5,6,7,8,9};
        System.out.println("input array");
        printArray(arrToReverse,7);
        int reversedArray[] = reverseArray(arrToReverse,0,7);
        System.out.println("output array");
        printArray(reversedArray,7);

    }

    /* Function to reverse arr[] from
    start to end*/
    private static int[] reverseArray(int arr[],int start,int end){
        int temp;
        while (start<end){
            temp = arr[start];
            arr[start] = arr[end];
            arr[end] = temp;
            start++;
            end--;
        }
        return arr;
    }

    //print the array element
    private static void printArray(int arr[], int size){
        for(int i:arr){
            System.out.print(i+" ");
        }
        System.out.println();
    }
}

     

Time Complexity - O(n)

Thanks a bunch for being here.

#stayhealthy

#takeCare

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Find another must-read post.

https://www.javaoneworld.com/2020/03/swap-two-numbers-using-bitwise-operator.html

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