Java Program to count words in a sentence using lambda expression

Last update on March 11 2025 14:02:02 (UTC/GMT +8 hours)

Count Words in a Sentence

Write a Java program to implement a lambda expression to count words in a sentence.

Sample Solution:

Java Code:

public class Main {
  public static void main(String[] args) {
    String text = "Java lambda expression.";
    System.out.println("Original string: " + text);
    WordCounter wordCounter = s -> s.split("\\s+").length;
    int ctr = wordCounter.countWords(text);
    System.out.println("Word count: " + ctr);
    text = "The quick brown fox jumps over the lazy dog.";
    System.out.println("\nOriginal string: " + text);
    wordCounter = s -> s.split("\\s+").length;
    ctr = wordCounter.countWords(text);
    System.out.println("Word count: " + ctr);
  }
}

@FunctionalInterface
interface WordCounter {
  int countWords(String text);
}

Sample Output:

Original string: Java lambda expression.
Word count: 3

Original string: The quick brown fox jumps over the lazy dog.
Word count: 9

Explanation:

In the above code the wordCounter variable is assigned a lambda expression that splits the input string by whitespace (\\s+) and counts the number of resulting substrings using the length method. The countWords method of the wordCounter instance is then called with the text string. The result is stored in the "ctr" variable. Finally, the word count is printed to the console.

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Java program to implement a lambda expression that counts words in a sentence after removing punctuation.
• Write a Java program to create a lambda that splits a sentence into words and filters out stop words before counting.
• Write a Java program to implement a lambda that maps each word in a sentence to its length and then sums these lengths.
• Write a Java program to chain lambda expressions to count the words and then output the most frequently occurring word.

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