path: root/rust/space-age/README.md

# Space Age

Welcome to Space Age on Exercism's Rust Track.
If you need help running the tests or submitting your code, check out `HELP.md`.

## Instructions

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](http://www.youtube.com/watch?v=Z_2gbGXzFbs).

Some Rust topics you may want to read about while solving this problem:

- Traits, both the From trait and implementing your own traits
- Default method implementations for traits
- Macros, the use of a macro could reduce boilerplate and increase readability 
  for this exercise. For instance, 
  [a macro can implement a trait for multiple types at once](https://stackoverflow.com/questions/39150216/implementing-a-trait-for-multiple-types-at-once),
  though it is fine to implement `years_during` in the Planet trait itself. A macro could
  define both the structs and their implementations. Info to get started with macros can 
  be found at:
  
  - [The Macros chapter in The Rust Programming Language](https://doc.rust-lang.org/stable/book/ch19-06-macros.html)
  - [an older version of the Macros chapter with helpful detail](https://doc.rust-lang.org/1.30.0/book/first-edition/macros.html)
  - [Rust By Example](https://doc.rust-lang.org/stable/rust-by-example/macros.html)

## Source

### Created by

- @IanWhitney

### Contributed to by

- @ashleygwilliams
- @bobahop
- @coriolinus
- @cwhakes
- @durka
- @eddyp
- @efx
- @ErikSchierboom
- @IanWhitney
- @joshgoebel
- @lutostag
- @nfiles
- @ocstl
- @petertseng
- @rofrol
- @stringparser
- @xakon
- @ZapAnton

### Based on

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