Reversing of char array using java

Hi everyone, in this blog post I will writing about reversing a char array using java. This program requires a char array as its input and it will return the reversed version of that char array.

The program which I have written to demonstrate reversing of char array is as follows:

package com.techjourney.methods;

public class ReversingCharArray {
    
    public static void main(String args[])
    {
        char firstArray[] = new char[]{'G','i','l','c','h','r','i','s','t'};
        char secondArray[] = new char[]{'D','r','a','v','i','d'};
        
        System.out.println(" First array before reversing - ");
        System.out.println(firstArray);
        
        System.out.println(" First array after reversing - ");
        charReversal(firstArray);
        System.out.println(firstArray);
        
        System.out.println(" Second array before reversing - ");
        System.out.println(secondArray);
        
        System.out.println(" Second array after reversing - ");
        charReversal(secondArray);
        System.out.println(secondArray);
    }
    
    public static char[] charReversal(char inputArray[])
    {
        if(inputArray==null)
        {
            throw new NullPointerException();
        }
        
        int lengthOfArray = inputArray.length;
        int elementPosition = lengthOfArray-1;
        char tempVariable;
        
        for(int i=0;i<lengthOfArray/2;i++)
        {
            tempVariable=inputArray[i];
            inputArray[i]=inputArray[elementPosition-i];
            inputArray[elementPosition-i] = tempVariable;
        }
        return inputArray;
        
    }    

}

In the above program, the function 'charReversal' reverses the input array. It does the reversing by the following steps:

• Finds the number of characters in the array and assigns it to variable 'lengthOfArray'.
• Iterate a loop from 0 to lengthOfArray/2.
• In the loop interchange the variables between first location and last location using a temp variable.
• Increment the pointer from first location and decrement the pointer from last location and continue the loop.

The output of the following program is as follows;

 First array before reversing - 
Gilchrist
 First array after reversing - 
tsirhcliG

 Second array before reversing - 
Dravid
 Second array after reversing - 
divarD

The length of arrays have odd as well as even values. This example was taken to demonstrate the program works for all the input values.

I hope everyone understood this program very well. Please do comment if you have any doubts or other queries.

Thank you everyone for reading the post.