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JaeHyoLee's solution

to Space Age in the Lua Track

Published at Jul 13 2018 · 0 comments
Instructions
Test suite
Solution

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

  • Earth: orbital period 365.25 Earth days, or 31557600 seconds
  • Mercury: orbital period 0.2408467 Earth years
  • Venus: orbital period 0.61519726 Earth years
  • 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.

Running the tests

To run the tests, run the command busted from within the exercise directory.

Further information

For more detailed information about the Lua track, including how to get help if you're having trouble, please visit the exercism.io Lua language page.

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.

space-age_spec.lua

local SpaceAge = require('space-age')

describe('space-age', function()
  it('age in seconds', function()
    local age = SpaceAge:new(1000000)
    assert.are.equal(1000000, age.seconds)
  end)

  it('age in Earth years', function()
    local age = SpaceAge:new(1000000000)
    assert.are.equal(31.69, age.on_earth())
  end)

  it('age in Mercury years', function()
    local age = SpaceAge:new(2134835688)
    assert.are.equal(67.65, age.on_earth())
    assert.are.equal(280.88, age.on_mercury())
  end)

  it('age in Venus years', function()
    local age = SpaceAge:new(189839836)
    assert.are.equal(6.02, age.on_earth())
    assert.are.equal(9.78, age.on_venus())
  end)

  it('age in Mars years', function()
    local age = SpaceAge:new(2329871239)
    assert.are.equal(73.83, age.on_earth())
    assert.are.equal(39.25, age.on_mars())
  end)

  it('age in Jupiter years', function()
    local age = SpaceAge:new(901876382)
    assert.are.equal(28.58, age.on_earth())
    assert.are.equal(2.41, age.on_jupiter())
  end)

  it('age in Saturn years', function()
    local age = SpaceAge:new(3000000000)
    assert.are.equal(95.06, age.on_earth())
    assert.are.equal(3.23, age.on_saturn())
  end)

  it('age in Uranus years', function()
    local age = SpaceAge:new(3210123456)
    assert.are.equal(101.72, age.on_earth())
    assert.are.equal(1.21, age.on_uranus())
  end)

  it('age in Neptune year', function()
    local age = SpaceAge:new(8210123456)
    assert.are.equal(260.16, age.on_earth())
    assert.are.equal(1.58, age.on_neptune())
  end)
end)
local space_age = {}

function space_age:new(seconds)

  local function calculator(earth_year)
    return function() return tonumber(string.format("%.2f", seconds/ 31557600 / earth_year)) end
  end

  return {
    seconds = seconds,
    on_earth = calculator(1),
    on_mercury = calculator(0.2408467),
    on_venus = calculator(0.61519726),
    on_mars =  calculator(1.8808158),
    on_jupiter = calculator(11.862615),
    on_saturn = calculator(29.447498),
    on_uranus = calculator(84.016846),
    on_neptune = calculator(164.79132)
  }
end

return space_age

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