In this blog post, we will discuss how to reverse the order of words in a Java array. We will explore a simple and efficient approach to achieve this using only a few lines of code.

Table of Contents

• Introduction
• Approach
• Implementation
• Conclusion

Introduction

Imagine you have an array of words in Java, and you want to reverse the order of those words. For example, if the original array is ["Hello", "World", "Java"], after reversing the order, the array should become ["Java", "World", "Hello"].

Approach

To reverse the order of words in a Java array, we can use a two-pointer technique. We will start with two pointers, one pointing to the beginning of the array and the other pointing to the end. We will swap the words pointed by both the pointers and increment the first pointer and decrement the second pointer until they meet in the middle.

Implementation

Let’s see how we can implement this approach in Java:

public class ArrayWordReversal {
    public static void reverseWords(String[] words) {
        int start = 0;
        int end = words.length - 1;

        while (start < end) {
            // Swap words at start and end pointers
            String temp = words[start];
            words[start] = words[end];
            words[end] = temp;

            // Move pointers towards the middle
            start++;
            end--;
        }
    }
    
    public static void main(String[] args) {
        String[] words = {"Hello", "World", "Java"};
        
        System.out.println("Original Array: " + Arrays.toString(words));
        reverseWords(words);
        System.out.println("Reversed Array: " + Arrays.toString(words));
    }
}

In the above code, we define a reverseWords method that takes an array of Strings as input and performs the reversal. We initialize the start and end pointers to the first and last indices of the array, respectively. Then, using a while loop, we swap the words at the start and end pointers and move the pointers towards the middle until they meet.

In the main method, we create a sample array of words and call the reverseWords method to reverse the order of words. Finally, we print the original and reversed arrays to verify the correctness of our implementation.

Conclusion

In this blog post, we explored how to reverse the order of words in a Java array. We learned a simple and efficient approach using a two-pointer technique. By swapping words at the start and end pointers and moving the pointers towards the middle, we were able to achieve the desired reversal. This technique can be useful in various scenarios where word rearrangement is required.