Question

Reversing an array is a common task. One approach copies to a second array in reverse, then copies the second array back to the first. However, to save space, reversing an array without using a second array is sometimes preferable. Write a code in java that reads in an integer representing the length of the array. Then read in and reverse the given array, without using a second array. If the original array's values are 2 5 9 7, the array after reversing is 7 9 5 2.

Hints:

• Use this approach: Swap the first and last elements, then swap the second and second-to-last elements, etc.

• Stop when you reach the middle; else, you'll reverse the vector twice, ending with the original order.

• Think about the case when the number of elements is even, and when odd. Make sure your code handles both cases.

Answer 1

Please find below code and don't forget to give a Like.

Please refer below screenshot for code and output

Code:

public class Main
{
   public static void main(String[] args) {
       int[] array={10,20,30,40,50,60};
       int temp;
       int rev=array.length-1;//from last element we decrement by 1
       int middle_element=array.length/2;
       //printing the original elements
       System.out.println("The original elements in array are:");
       for(int i=0;i<array.length;i++){
       System.out.println(array[i]);
       }
       for(int i=0;i<=middle_element;i++){
       temp=array[i];//storing 1st element in temporary varible
       array[i]=array[rev];//assigning last element into first
       //swaping last element with temporary value which is saved
       array[rev]=temp;
       rev-=1//starting from last element will be decrement by 1
       }
       //printing thr reverse array
       System.out.println("The reverse elements are:");
       for(int i=0;i<array.length;i++){
       System.out.println(array[i]);
       }
   }
}

Output: