function numVowels (str) {
    let count = 0;

    // Iterate over each character in the string
    for (let i=0; i<str.length; i++) {
        // check whether this character (in lower case) is a, e, i, o, or u (converting in lower case would reduce the amount of conditons by half since there would be no need to check A, E, I, O or U)
        if (
            str[i].toLowerCase() === 'a' ||
            str[i].toLowerCase() === 'e' ||
            str[i].toLowerCase() === 'i' ||
            str[i].toLowerCase() === 'o' ||
            str[i].toLowerCase() === 'u'
        ) {
            count++;
        }
    }

    // Print and return the number of vowels
    console.log(`The number of vowels in ${str} is = ${count}`);
    return count;
}

numVowels ('hello');
numVowels ('Greetings');

function numVowels (str) {
    let count = 0;

    // Define a vowels array
    let vowels = ['a', 'e', 'i', 'o', 'u'];

    // Iterate over each character in the string
    for (let i=0; i<str.length; i++) {
        // check whether this character (in lower case) is a, e, i, o, or u (converting in lower case would reduce the amount of conditons by half since there would be no need to check A, E, I, O or U)
        if (vowels.indexOf(str[i].toLowerCase()) >= 0) {
            count++;
        }
    }

    // Print and return the number of vowels
    console.log(`The number of vowels in ${str} is = ${count}`);
    return count;
}

numVowels ('hEllo');
numVowels ('Greetings');

// Store vowels in an array
// check each character of the string with each element in vowels array

function numVowels (str) {
    // Initialize count to be zero
    let count = 0;

    // Define an array of vowels
    let vowels = ['a', 'e', 'i', 'o', 'u'];

    // Check each character of string
    for (let char of str) {
        for (let vowel of vowels) {
            if (char.toLowerCase() === vowel)  count++;
        }
    }

    // Print the result
    console.log(`The number of vowels in "${str}" is = ${count}`);
    return count;
}

numVowels ('hello');
numVowels ('Greetings');

// Similar to previous method
// Instead of storing vowels in an array, store them in an object as keys and values as the number of occurances

function numVowels (str) {
    console.log('\nString: ', str);

    // Initialize count to be zero
    let count = 0;

    // Store the vowels in an object
    let vowels = {
        'a': 0,
        'b': 0,
        'c': 0,
        'd': 0,
        'e': 0
    };

    // Iterate through each character of string to check vowels
    for (let char of str) {
        for (vowel in vowels) {
            if (char.toLowerCase() === vowel) {
                count++;
                vowels[vowel]++;
            }
        }
    }

    // Print the result
    console.log('Vowel Count: ');
    for (let vowel in vowels) {
        console.log(`Vowel: ${vowel} appears ${vowels[vowel]} number of times in the string "${str}"`);
    }

    console.log("Total number of vowels: " + count);
    return count;
}

numVowels ('hello');
numVowels ('Greetings');

function maxChars (str) {
    let letterCount = {};

    // Complete the letter count object
    for(let currentChar of str) {
        let flag = 0;
        for (letter in letterCount) {
            if (currentChar.toLowerCase() === letter) {
                flag = 1;
                letterCount[letter]++;
            }
        }

        if (flag === 0) {
            letterCount[currentChar] = 1;
        }
    }

    // Find the maximum value key from the letterCount
    let max = 0, maxChar = '';
    for (letter in letterCount) {
        if (letterCount[letter] >= max) {
            max = letterCount[letter];
            maxChar = letter;
        }
    }

    // Print the result
    console.log(`The maximum frequency letter is: "${maxChar}" and it appears ${letterCount[maxChar]} number of times!`);
    return letterCount[maxChar];
}

maxChars('helllllo worlld');

function maxChars (sentence) {
    let characters = {};

    // Update characters object with count of each character in sentence
    for (let letter of sentence) {
        // increment the count of existing letter OR add the new character with value = 1
        characters[letter] = characters[letter] + 1 || 1;
    }

    let max = 0,
      maxChar = '';

    for (let character in characters) {
        if (max < characters[character]) {
            max = characters[character];
            maxChar = character;
        }
    }

    // Print the result
    console.log(`The maximum frequency letter is: "${maxChar}" and it appears ${characters[maxChar]} number of times!`);
    return characters[maxChar];
}

maxChars('helllllo worlld');