 # kpreston1's solution

## to Space Age in the Scala Track

Published at Oct 16 2019 · 0 comments
Instructions
Test suite
Solution

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.

## Source

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.

### SpaceAgeTest.scala

``````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") {
pending
SpaceAge.onMercury(2134835688) should be (280.88 +- 0.01)
}

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

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

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

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

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

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

val MERCURY = "MERCURY"
val VENUS = "VENUS"
val EARTH = "EARTH"
val MARS = "MARS"
val JUPITER = "JUPITER"
val SATURN = "SATURN"
val URANUS = "URANUS"
val NEPTUNE = "NEPTUNE"

val MERCURY_ORBITAL_PERIOD: Double = 0.2408467
val VENUS_ORBITAL_PERIOD: Double = 0.61519726
val EARTH_ORBITAL_PERIOD: Double = 1.0
val MARS_ORBITAL_PERIOD: Double = 1.8808158
val JUPITER_ORBITAL_PERIOD: Double = 11.862615
val SATURN_ORBITAL_PERIOD: Double = 29.447498
val URANUS_ORBITAL_PERIOD: Double = 84.016846
val NEPTUNE_ORBITAL_PERIOD: Double = 164.79132

val EARTH_ORBITAL_PERIOD_IN_SECONDS: Double = 31557600

def onMercury(age: Double): Double =
calculateEarthAge(age, planetOrbitalPeriodMatch(MERCURY))
def onVenus(age: Double): Double   =
calculateEarthAge(age, planetOrbitalPeriodMatch(VENUS))
def onEarth(age: Double): Double   =
calculateEarthAge(age, planetOrbitalPeriodMatch(EARTH))
def onMars(age: Double): Double    =
calculateEarthAge(age, planetOrbitalPeriodMatch(MARS))
def onJupiter(age: Double): Double =
calculateEarthAge(age, planetOrbitalPeriodMatch(JUPITER))
def onSaturn(age: Double): Double  =
calculateEarthAge(age, planetOrbitalPeriodMatch(SATURN))
def onUranus(age: Double): Double  =
calculateEarthAge(age, planetOrbitalPeriodMatch(URANUS))
def onNeptune(age: Double): Double =
calculateEarthAge(age, planetOrbitalPeriodMatch(NEPTUNE))

def calculateEarthAge(age: Double, orbitalPeriod: Double): Double =
age / ( orbitalPeriod * EARTH_ORBITAL_PERIOD_IN_SECONDS )

def planetOrbitalPeriodMatch(planetName: String): Double = planetName match {
case MERCURY => MERCURY_ORBITAL_PERIOD
case VENUS => VENUS_ORBITAL_PERIOD
case EARTH => EARTH_ORBITAL_PERIOD
case MARS => MARS_ORBITAL_PERIOD
case JUPITER => JUPITER_ORBITAL_PERIOD
case SATURN => SATURN_ORBITAL_PERIOD
case URANUS => URANUS_ORBITAL_PERIOD
case NEPTUNE => NEPTUNE_ORBITAL_PERIOD
}
}``````