79 lines
2.8 KiB
Markdown
79 lines
2.8 KiB
Markdown
# Roman Numerals
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Write a function to convert from normal numbers to Roman Numerals: e.g.
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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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```
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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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## Getting Started
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Make sure you have read the [getting started with C++](http://help.exercism.io/getting-started-with-cpp.html)
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page on the [exercism help site](http://help.exercism.io/). This covers
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the basic information on setting up the development environment expected
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by the exercises.
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## Passing the Tests
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Get the first test compiling, linking and passing by following the [three
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rules of test-driven development](http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd).
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Create just enough structure by declaring namespaces, functions, classes,
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etc., to satisfy any compiler errors and get the test to fail. Then write
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just enough code to get the test to pass. Once you've done that,
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uncomment the next test by moving the following line past the next test.
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```C++
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#if defined(EXERCISM_RUN_ALL_TESTS)
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```
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This may result in compile errors as new constructs may be invoked that
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you haven't yet declared or defined. Again, fix the compile errors minimally
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to get a failing test, then change the code minimally to pass the test,
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refactor your implementation for readability and expressiveness and then
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go on to the next test.
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Try to use standard C++11 facilities in preference to writing your own
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low-level algorithms or facilities by hand. [CppReference](http://en.cppreference.com/)
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is a wiki reference to the C++ language and standard library. If you
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are new to C++, but have programmed in C, beware of
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[C traps and pitfalls](http://www.slideshare.net/LegalizeAdulthood/c-traps-and-pitfalls-for-c-programmers).
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## Source
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The Roman Numeral Kata [view source](http://codingdojo.org/cgi-bin/wiki.pl?KataRomanNumerals)
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