Exercises

Recap Questions

WIP

Exercises

Write a function called getAverage that takes an array of numbers as parameter, and calculates their average value.

Hint: you already know how to calculate the sum of an array of numbers.

Details

Possible solution

As said, we already know how to sum an array of numbers:

function sumNumbers(numbers) {
  let partialSum = 0;
  for (let i = 0; i < numbers.length; i++) {
    partialSum = partialSum + numbers[i];
  }
  return partialSum;
}

The formula for the average value of a list of number is their sum times how many numbers we have. We can access this information via the length property of the array, so:

function getAverage(numbers) {
  let partialSum = 0;
  
  for (let i = 0; i < numbers.length; i++) {
    partialSum = partialSum + numbers[i];
  }

  return partialSum / numbers.length;
}

console.log('The average value of 2, 3, 4 is', getAverage([2, 3, 4]));

Toggle Console Output

• The average value of 234 is 3

Even better it would be to reuse the sumNumbers function:

function sumNumbers(numbers) {
  let partialSum = 0;

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

  return partialSum;
}

function getAverage(numbers) {
  return sumNumbers(numbers) / numbers.length;
}

console.log('The average value of 2, 3, 4 is', getAverage([2, 3, 4]));

Toggle Console Output

• The average value of 234 is 3