Java Program to reverse words in a given string

Program

import java.util.Scanner;
public class ReverseWordsInString {
    public void reverseWords(String string)
    {
        String str[] = string.split(" ");
        String reversedString = "";
        for (int i = str.length - 1; i >= 0; i--) 
        { 
            reversedString += str[i] + " ";         
        }
      System.out.println("Reverse of the given string is: "+ reversedString);
    }
    public static void main(String[] args){
        ReverseWordsInString reverseWordsInString = new ReverseWordsInString();
        Scanner reader = new Scanner(System.in);
        System.out.println("Enter a string to reverse: ");
        String enteredString = reader.nextLine();
        reverseWordsInString.reverseWords(enteredString);        
    }
}

This program reverses the order of words in a given string by splitting the string into an array of words and concatenating them in reverse order.

Use Case:

This program is helpful in situations where word order needs to be reversed, such as text processing, natural language processing tasks, or formatting outputs.

1. Input:

   • The program uses the Scanner class to accept a string from the user.

2. Splitting the String:

   • string.split(" "):
     • Splits the input string into an array of words based on spaces.

3. Reversing the Words:

   • A for loop iterates through the array of words from the last index to the first index.
   • Each word is added to a new string (reversedString) with a space.

4. Output:

   • The reversed string is printed with the words in reverse order.

5. Example Execution:

   • Example Input:

     Enter a string to reverse: Hello World from Java
     

   • Process:
     • Split the string: ["Hello", "World", "from", "Java"].
     • Reverse and concatenate: "Java from World Hello ".
   • Output:

     Reverse of the given string is: Java from World Hello 
     

Key Features:

• String Manipulation:
  • Splits the string into words and reverses their order.
• Simple Logic:
  • Uses a straightforward loop to reverse the array of words.
• Space Preservation:
  • Adds a space after each word in the reversed string.

Output

$ javac ReverseWordsInString.java
$ java ReverseWordsInString
Enter a string to reverse:
oodlescoop tutorials and programs
Reverse of the given string is: programs and tutorials oodlescoop