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to Space Age in the Scala Track

Published at Oct 17 2019 · 0 comments
Test suite

Given an age in seconds, calculate how old someone would be on:

  • Mercury: orbital period 0.2408467 Earth years
  • Venus: orbital period 0.61519726 Earth years
  • Earth: orbital period 1.0 Earth years, 365.25 Earth days, or 31557600 seconds
  • Mars: orbital period 1.8808158 Earth years
  • Jupiter: orbital period 11.862615 Earth years
  • Saturn: orbital period 29.447498 Earth years
  • Uranus: orbital period 84.016846 Earth years
  • Neptune: orbital period 164.79132 Earth years

So if you were told someone were 1,000,000,000 seconds old, you should be able to say that they're 31.69 Earth-years old.

If you're wondering why Pluto didn't make the cut, go watch this youtube video.

The Scala exercises assume an SBT project scheme. The exercise solution source should be placed within the exercise directory/src/main/scala. The exercise unit tests can be found within the exercise directory/src/test/scala.

To run the tests simply run the command sbt test in the exercise directory.

Please see the learning and installation pages if you need any help.


Partially inspired by Chapter 1 in Chris Pine's online Learn to Program tutorial. http://pine.fm/LearnToProgram/?Chapter=01

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.


import org.scalatest.{Matchers, FunSuite}

/** @version 1.1.0 */
class SpaceAgeTest extends FunSuite with Matchers {

  test("age on Earth") {
    SpaceAge.onEarth(1000000000) should be (31.69 +- 0.01)

  test("age on Mercury") {
    SpaceAge.onMercury(2134835688) should be (280.88 +- 0.01)

  test("age on Venus") {
    SpaceAge.onVenus(189839836) should be (9.78 +- 0.01)

  test("age on Mars") {
    SpaceAge.onMars(2.329871239E9) should be (39.25 +- 0.01)

  test("age on Jupiter") {
    SpaceAge.onJupiter(901876382) should be (2.41 +- 0.01)

  test("age on Saturn") {
    SpaceAge.onSaturn(3.0E9) should be (3.23 +- 0.01)

  test("age on Uranus") {
    SpaceAge.onUranus(3.210123456E9) should be (1.21 +- 0.01)

  test("age on Neptune") {
    SpaceAge.onNeptune(8.210123456E9) should be (1.58 +- 0.01)
object SpaceAge{

    private val earthYearInSeconds  = 31557600
    private val baseOrbitalPeriod  = 1
    private val mercuryOrbitalPeriod  = 0.2408467
    private val venusOrbitalPeriod  = 0.615197260
    private val marsOrbitalPeriod  = 1.8808158
    private val jupiterOrbitalPeriod  = 11.862615
    private val saturnOrbitalPeriod  = 29.447498
    private val uranusOrbitalPeriod  = 84.016846
    private val neptuneOrbitalPeriod  = 164.79132    

    private def howOldInYears(ageInSeconds: Double, orbitalPeriod: Double): Double =
     ageInSeconds / earthYearInSeconds / orbitalPeriod

    def onEarth(ageInSeconds: Double): Double = howOldInYears(ageInSeconds, baseOrbitalPeriod)

    def onMercury(ageInSeconds: Double): Double = howOldInYears(ageInSeconds, mercuryOrbitalPeriod)

    def onVenus(ageInSeconds: Double): Double = howOldInYears(ageInSeconds, venusOrbitalPeriod)

    def onMars(ageInSeconds: Double): Double = howOldInYears(ageInSeconds, marsOrbitalPeriod)

    def onJupiter(ageInSeconds: Double): Double = howOldInYears(ageInSeconds, jupiterOrbitalPeriod)

    def onSaturn(ageInSeconds: Double): Double = howOldInYears(ageInSeconds, saturnOrbitalPeriod)

    def onUranus(ageInSeconds: Double): Double = howOldInYears(ageInSeconds, uranusOrbitalPeriod)

    def onNeptune(ageInSeconds: Double): Double = howOldInYears(ageInSeconds, neptuneOrbitalPeriod)

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