74 lines
2.1 KiB
Markdown
74 lines
2.1 KiB
Markdown
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# Roman Numerals
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Write a function to convert from normal numbers to Roman Numerals.
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The Romans were a clever bunch. They conquered most of Europe and ruled
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it for hundreds of years. They invented concrete and straight roads and
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even bikinis. One thing they never discovered though was the number
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zero. This made writing and dating extensive histories of their exploits
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slightly more challenging, but the system of numbers they came up with
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is still in use today. For example the BBC uses Roman numerals to date
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their programmes.
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The Romans wrote numbers using letters - I, V, X, L, C, D, M. (notice
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these letters have lots of straight lines and are hence easy to hack
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into stone tablets).
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```text
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1 => I
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10 => X
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7 => VII
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```
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There is no need to be able to convert numbers larger than about 3000.
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(The Romans themselves didn't tend to go any higher)
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Wikipedia says: Modern Roman numerals ... are written by expressing each
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digit separately starting with the left most digit and skipping any
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digit with a value of zero.
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To see this in practice, consider the example of 1990.
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In Roman numerals 1990 is MCMXC:
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1000=M
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900=CM
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90=XC
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2008 is written as MMVIII:
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2000=MM
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8=VIII
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See also: http://www.novaroma.org/via_romana/numbers.html
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* * * *
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For installation and learning resources, refer to the
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[exercism help page](http://exercism.io/languages/ruby).
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For running the tests provided, you will need the Minitest gem. Open a
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terminal window and run the following command to install minitest:
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gem install minitest
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If you would like color output, you can `require 'minitest/pride'` in
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the test file, or note the alternative instruction, below, for running
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the test file.
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Run the tests from the exercise directory using the following command:
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ruby roman_numerals_test.rb
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To include color from the command line:
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ruby -r minitest/pride roman_numerals_test.rb
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## Source
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The Roman Numeral Kata [http://codingdojo.org/cgi-bin/index.pl?KataRomanNumerals](http://codingdojo.org/cgi-bin/index.pl?KataRomanNumerals)
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## Submitting Incomplete Solutions
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It's possible to submit an incomplete solution so you can see how others have completed the exercise.
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