count_vowels_in_a_string.md

Count Vowels in a String

Count Vowels in a String

To count the vowels in a string, iterate through the string and check if each character is a vowel.

Algorithm:

1. Normalize the string by converting it to lowercase to handle case insensitivity.
2. Define a set or array containing all vowel characters (a, e, i, o, u).
3. Iterate through the string and count characters that match any vowel.
4. Return the total count of vowels.

Example:

function countVowels(str) {
    const vowels = new Set(['a', 'e', 'i', 'o', 'u']);
    let count = 0;

    for (const char of str.toLowerCase()) {
        if (vowels.has(char)) {
            count++;
        }
    }

    return count;
}

// Example usage
console.log(countVowels("Hello World")); // Output: 3
console.log(countVowels("JavaScript is awesome!")); // Output: 8

This method has a time complexity of O(n), where n is the length of the string.

Tags: basic, JavaScript, Strings, Algorithm