Java Program to Count Number of Words in String

In this blog post, we will write a Java program that counts the number of words in a given string. This program uses string manipulation techniques to split the input string into individual words and then count them. It provides a simple and efficient way to determine the word count in a text. Let's explore the code and see how it works!

In this post, we discuss three different approaches to writing a Java program to count a number of words in given input String.

Approach 1: Using the split() Method

In this program, we use the split() method to split the input string into words based on one or more whitespace characters (\\s+). The resulting words are stored in an array, and the length of the array gives the word count.

public class WordCount {
    public static void main(String[] args) {
        String inputString = "Java is a programming language.";

        // Removing leading and trailing whitespaces
        inputString = inputString.trim();

        // Splitting the string into words
        String[] words = inputString.split("\\s+");

        // Counting the number of words
        int wordCount = words.length;

        System.out.println("Number of words: " + wordCount);
    }
}

Output:

Number of words: 5

Approach 2: Using StringTokenizer

In this program, we use the StringTokenizer class to tokenize the input string by default delimiters, which include whitespace characters. The countTokens() method provides the word count.

import java.util.StringTokenizer;

public class WordCount {
    public static void main(String[] args) {
        String inputString = "Java is a programming language.";

        // Creating a StringTokenizer object
        StringTokenizer tokenizer = new StringTokenizer(inputString);

        // Counting the number of words
        int wordCount = tokenizer.countTokens();

        System.out.println("Number of words: " + wordCount);
    }
}

Output:

Number of words: 5

Approach 3: Using Regular Expressions

In this program, we will use a regular expression (\\b\\w+\\b) to define a pattern that matches individual words. A Matcher object is created based on the pattern, and the find() method is used in a loop to find all word occurrences. The count is incremented for each match.

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class WordCount {
    public static void main(String[] args) {
        String inputString = "Java is a programming language.";

        // Creating a pattern to match words
        Pattern pattern = Pattern.compile("\\b\\w+\\b");

        // Creating a matcher object
        Matcher matcher = pattern.matcher(inputString);

        // Counting the number of words
        int wordCount = 0;
        while (matcher.find()) {
            wordCount++;
        }

        System.out.println("Number of words: " + wordCount);
    }
}

Conclusion

In this blog post, we explored different ways to write a Java program to count the number of words in a given string. These approaches provide flexibility in implementing word-counting logic based on personal preferences or specific requirements. You can choose the approach that best suits your needs and integrate it into your Java projects. 

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