Programming Basics - Session 6 (Exercise answers)

exercises.js

// EXERCISE 3:
// ---------------------------------------------------------------------------------------------- /
// 3.1
// ---------------------------------------------------------------------------------------------- /
const alphabet = 'abcdefghijklmnopqrstuvwxyz';
const createProduct = (title, price) => {
  return [title, price];
};

let productList = [];

for (let i = 0; i < 5; i++) {
  const character = alphabet[i];
  const title = 'Product ' + character; // or: const title = `Product ${character}`;
  const price = (i + 1) * 10;
  const product = createProduct(title, price);

  productList.push(product);
}

console.log(productList);



// ---------------------------------------------------------------------------------------------- /
// 3.2
// ---------------------------------------------------------------------------------------------- /
const startsAndEndsWith = (text, character) => {
  return text.startWith(character) && text.endsWith(character);
};

console.log(startsAndEndsWith('hello world', 'h'));
console.log(startsAndEndsWith('billy bob', 'b'));

// - BONUS POINTS: ------------------------------------------------------------------------------ /
const startsAndEndsWith = (text, character) => {
  const lowercasedInput = text.toLowerCase();
  const lowercasedCharacter = character.toLowerCase();

  return (
    lowercasedInput.startWith(lowercasedCharacter) && lowercasedInput.endsWith(lowercasedCharacter)
  );
};

console.log(startsAndEndsWith("Bobby's Blob", 'b'));
console.log(startsAndEndsWith('perryP', 'p'));
console.log(startsAndEndsWith('bloB', 'B'));


// ---------------------------------------------------------------------------------------------- /
// 3.3
// ---------------------------------------------------------------------------------------------- /
const order1 = [
  ['Awesome Product A', 25],
  ['Awesome Product B', 10],
  ['Awesome Product C', 12],
];
const order2 = [
  ['Awesome Product A', 25],
  ['Awesome Product C', 12],
  ['Awesome Product C', 12],
  ['Awesome Product C', 12],
  ['Awesome Product D', 8],
];

let totalToCharge = 0;

const getPriceForOrder = order => {
  let total = 0;

  for (let i = 0; i < order.length; i++) {
    const product = order[i];
    const productPrice = product[1];

    total += productPrice;
  }

  return total;
};

totalToCharge = getPriceForOrder(order1) + getPriceForOrder(order2);
console.log(totalToCharge);

// - BONUS POINTS: ------------------------------------------------------------------------------ /
function getTotalFromOrders(orders) {
  let totalForAllOrders = 0;

  // add calculation here
  for (let i = 0; i < orders.length; i++) {
    const order = orders[i];

    totalForAllOrders = totalForAllOrders + getPriceForOrder(order);
  }

  return totalForAllOrders;
}

console.log(getTotalFromOrders([order1, order2]));


// ---------------------------------------------------------------------------------------------- /
// 3.4
// ---------------------------------------------------------------------------------------------- /
const toUpperCase = input => {
  let output = '';

  for (let i = 0; i < input.length; i++) {
    const character = input[i];

    output += character.toUpperCase();
  }

  return output;
};

console.log(toUpperCase('Boyd'));
console.log(toUpperCase('you'));
console.log(toUpperCase('deserve'));
console.log(toUpperCase('a'));
console.log(toUpperCase('break'));


// ---------------------------------------------------------------------------------------------- /
// 3.5
// ---------------------------------------------------------------------------------------------- /
const reverse = arr => {
  let newArray = [];
  const lastIndex = arr.length - 1;

  for (let i = lastIndex; i >= 0; i--) {
    const item = arr[i];

    newArray.push(item);
  }

  return newArray;
};

console.log(reverse([1, 2, 3, 4]));
console.log(reverse([]));
console.log(reverse(['Kreeft', 'Nijlpaard', 'Ezel']));


// ---------------------------------------------------------------------------------------------- /
// 3.6
// ---------------------------------------------------------------------------------------------- /
const order99 = [
  ['Awesome Product A', 25],
  ['Awesome Product C', 12],
  ['Awesome Product C', 12],
  ['Awesome Product C', 12],
  ['Awesome Product D', 8],
  ['Awesome Product X', 999],
];

function sum(numbers) {
  let total = 0;

  for (let i = 0; i < numbers.length; i++) {
    const number = numbers[i];

    total += number;
  }

  return total;
}

const average = numbers => {
  return sum(numbers) / numbers.length;
};

const averagePriceOfOrder = order => {
  let prices = [];

  for (let i = 0; i < order.length; i++) {
    const product = order[i];
    const productPrice = product[1];

    prices.push(productPrice);
  }

  return average(prices);
};

const orderAveragePrice = averagePriceOfOrder(order99);

console.log(orderAveragePrice);






// EXERCISE 4:
// ---------------------------------------------------------------------------------------------- /
// 4
// ---------------------------------------------------------------------------------------------- /
let isPoweredOn = false;

function pressPowerButton() {
  if (isPoweredOn) {
    console.log('Turning off the machine...');
    isPoweredOn = false;
  } else {
    console.log('Turning on the machine...');
    isPoweredOn = true;
  }
}

console.log(isPoweredOn);
pressPowerButton();
console.log(isPoweredOn);
pressPowerButton();
console.log(isPoweredOn);