Problem-2_Count_Vowels_in_a_String.js

// Problem-2_Count_Vowels_in_a_String with Solution, Explanation, Verification, and Execution:

// To count vowels in a string, we can implement the Solution like below:
// -------------------------------------------------------------------

function countVowels(str) {
    let count = 0;
    const vowels = 'aeiouAEIOU';
    for (let char of str) {
        if (vowels.includes(char)) {
            count++;
        }
    }
    return count;
}

// Explanation: 
// ---------------
// The function starts with a counter set to zero and defines a string containing all vowels (both lowercase and uppercase for case-insensitivity). It loops through each character in the input string using a for-of loop. For each character, it checks if it is included in the vowels string; if so, the counter increments. This method scans the string sequentially, tallying matches without relying on regular expressions or complex filtering, making it simple to follow.

// Verification:
// ----------------

// function countVowels(programming) {
//     let count = 0;
//     const vowels = 'aeiouAEIOU';
//     for (let char of programming) {
//         if (vowels.includes(char)) {
//             count++;
//         }
//     }
//     return count;
// }
// console.log(countVowels("programming"));

// Execution of the above code block in IDE environment with node.js installed:
// ----------------------------------------------------------------------
// Input (In the directory in IDE environment with node.js installed): 'node Problem-2_Count_Vowels_in_a_String.js'
// Output (In the directory in IDE environment with node.js installed): 3