Java: Reverse the content of a sentence without reverse every word

Java Basic: Exercise-169 with Solution

Write a Java program to reverse a sentence (assume a single space between two words) without reverse every word.

Visual Presentation:

Sample Solution:

Java Code:

// Importing the required Java utilities package
import java.util.*;

// Defining a class named Solution
public class Solution {
  
  // Method to reverse the words in a given string
  public static String reverse_str_word(String input_sentence) {
    // Checking if the input string is null
    if (input_sentence == null) {
      throw new IllegalArgumentException("Input param can't be null."); // Throwing an exception for null input
    }
    
    StringBuilder stringBuilder = new StringBuilder(); // Creating a StringBuilder to store the reversed string
    String[] words = input_sentence.split(" "); // Splitting the input sentence into words based on spaces
    
    // Loop to append words in reverse order to the StringBuilder
    for (int i = words.length - 1; i >= 0; i--) {
      stringBuilder.append(words[i]); // Appending each word in reverse order
      
      if (i != 0) {
        stringBuilder.append(" "); // Adding space between words except for the last word
      }
    }
    
    return stringBuilder.toString(); // Returning the reversed string of words
  }
  
  // The main method of the program
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in); // Creating a Scanner object to read input from the user
    
    // Asking the user to input a string
    System.out.print("Input a string: ");
    String input = scanner.nextLine(); // Reading the input string from the user
    
    // Displaying the result by reversing the words in the input string
    System.out.println("\nResult: " + reverse_str_word(input));
  }
} 

Sample Output:

Input a string:  The quick brown fox jumps over the lazy dog

Result: dog lazy the over jumps fox brown quick The

Flowchart:

Java Code Editor:

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