Java Program to Count Vowels and Consonants in a String

Introduction

Counting the number of vowels and consonants in a string is a common task in text processing. This exercise helps you understand string manipulation and the use of loops and conditionals in Java. This guide will walk you through writing a Java program that counts the number of vowels and consonants in a given string.

Problem Statement

Create a Java program that:

• Prompts the user to enter a string.
• Counts the number of vowels in the string.
• Counts the number of consonants in the string.
• Displays the counts for both vowels and consonants.

Example:

• Input: "Hello World"
• Output:

  Number of vowels: 3 Number of consonants: 7 

Solution Steps

1. Read the String: Use the Scanner class to take the string as input from the user.
2. Initialize Counters: Create variables to store the count of vowels and consonants.
3. Iterate Through the String: Loop through each character in the string and check if it is a vowel or a consonant.
4. Display the Counts: Print the counts of vowels and consonants.

Java Program

// Java Program to Count Vowels and Consonants in a String // Author: https://www.rameshfadatare.com/ import java.util.Scanner; public class VowelConsonantCounter { public static void main(String[] args) { // Step 1: Read the string from the user try (Scanner scanner = new Scanner(System.in)) { System.out.print("Enter a string: "); String input = scanner.nextLine(); // Step 2: Initialize the vowel and consonant counters int vowelCount = 0; int consonantCount = 0; // Step 3: Iterate through the string for (int i = 0; i < input.length(); i++) { char ch = input.charAt(i); // Check if the character is a vowel if (isVowel(ch)) { vowelCount++; } // Check if the character is a consonant else if (isConsonant(ch)) { consonantCount++; } } // Step 4: Display the counts System.out.println("Number of vowels: " + vowelCount); System.out.println("Number of consonants: " + consonantCount); } } // Helper method to check if a character is a vowel public static boolean isVowel(char ch) { ch = Character.toLowerCase(ch); return ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u'; } // Helper method to check if a character is a consonant public static boolean isConsonant(char ch) { ch = Character.toLowerCase(ch); return ch >= 'a' && ch <= 'z' && !isVowel(ch); } } 

Explanation

Step 1: Read the String

• The Scanner class is used to read a string input from the user. The nextLine() method captures the entire line as a string.

Step 2: Initialize Counters

• Two integer variables vowelCount and consonantCount are initialized to zero. These will hold the counts of vowels and consonants found in the string.

Step 3: Iterate Through the String

• A for loop is used to iterate over each character in the string, using the charAt() method to access individual characters.
• The isVowel() method checks if a character is a vowel.
• The isConsonant() method checks if a character is a consonant.

Step 4: Display the Counts

• The program prints the total number of vowels and consonants found in the string using System.out.println().

Output Example

Example:

Enter a string: Hello World Number of vowels: 3 Number of consonants: 7 

Conclusion

This Java program demonstrates how to count and display the number of vowels and consonants in a user-input string. It covers essential concepts such as string manipulation, loops, and conditionals, making it a useful exercise for beginners learning Java programming.