Day 2 - Challenge 3 - Counting Vowels in string

Counting Vowels in JavaScript: A Simple Problem

Are you ready to dive into a classic programming challenge? In this blog post, we'll explore a simple yet fundamental problem: counting the number of vowels in a given string using JavaScript. Whether you're new to programming or looking to refresh your skills, this problem is a great exercise to enhance your understanding of string manipulation, loops, and arrays. So, let's get started!

The Problem

Our task is to write a JavaScript program that takes a string as input and returns the count of vowels present in that string. Vowels are the letters 'a', 'e', 'i', 'o', and 'u', regardless of their case. This means that both uppercase and lowercase vowels should be considered when counting.

The Approach

To solve this problem, we can break it down into a few simple steps:

1. Convert to Lowercase: To ensure that we count both uppercase and lowercase vowels, we should first convert the entire input string to lowercase. This way, we can work with a standardized format.

2. Define the Vowels: Create an array that contains the vowel characters ('a', 'e', 'i', 'o', 'u'). This array will help us check whether a given character is a vowel or not.

3. Loop Through the String: Use a loop to iterate through each character of the lowercase string.

4. Count Vowels: Inside the loop, check if the current character exists in the vowel array. If it does, increment a counter variable to keep track of the number of vowels encountered.

5. Return the Count: After looping through the entire string, return the final count of vowels.

The JavaScript Code

Let's take a look at the JavaScript code that implements the solution:

function countVowels(str) {
  const lowerStr = str.toLowerCase();
  const vowels = ['a', 'e', 'i', 'o', 'u'];
  let vowelCount = 0;
  
  for (let char of lowerStr) {
    if (vowels.includes(char)) {
      vowelCount++;
    }
  }
  
  return vowelCount;
}

// Example usage
const inputString = "Hello, how are you?";
const numVowels = countVowels(inputString);
console.log(`Number of vowels: ${numVowels}`);

This program defines a function called countVowels that takes a string as input and returns the count of vowels in the string. It converts the input string to lowercase to handle both uppercase and lowercase vowels. Then, it loops through each character in the string and checks if the character is a vowel using the includes method on the vowels array. If the character is a vowel, the vowelCount is incremented. Finally, the function returns the total count of vowels.

Demo

Vowel Counter

Number of vowels: 0

Testing the Solution

You can test the program with various input strings, both simple and complex. Try inputting sentences, phrases, or even paragraphs to see how the program accurately counts the vowels each time.

Conclusion

Congratulations! You've successfully tackled the "Vowel Counter" problem using JavaScript. This exercise not only helped you practice string manipulation and array usage but also encouraged you to think logically and break down a problem into manageable steps. As you continue your programming journey, remember that even seemingly simple challenges like this one play a vital role in strengthening your coding skills.

Now write the program to count vowel in your language in comments.

Complete Other Challenges: 

1. Day 1 Challenges
2. Day 2 Challenge 1
3. Day 2 Challenge 2