From: Hung Dao <mephis1987@...>
Date: 2006-12-10T20:53:30+09:00
Subject: Re: Need help on a program

class Integer def to_roman   Hash["M", 1000, "D", 500, "C", 100, "L", 50, "X", 10, "V", 5, "I",1].sort_by{|a| -a.last}.inject( [ "", self ] ){|roman, pair|     [ (pair.last - roman.last ==1 )? roman.first+"I"+pair.first :roman.first + pair.first * (roman.last / pair.last),       roman.last % pair.last ] }.   first endend
I noticed that your code is partly wrong since it will output IIII for4 and so on , I have modified it a little bit , but I have not checkedthe result
RegardsOn 12/9/06, William James <w_a_x_man@yahoo.com> wrote:> Christopher Latif wrote:> > Stuck on this exercise from a book:> > Old-school Roman numerals. In the early days of Roman numerals,> > the Romans didn't bother with any of this new-fangled subtraction> > "IX" nonsense. No sir, it was straight addition, biggest to littlest-> > so 9 was written "VIIII," and so on. Write a method that, when> > passed an integer between 1 and 3000 (or so), returns a string> > containing the proper old-school Roman numeral. In other words,> > old_roman_numeral 4 should return 'IIII'. Make sure to test> > your method on a bunch of different numbers.> > For reference, these are the values of the letters used:> > I =1       V =5      X = 10       L = 50> > C = 100    D = 500   M = 1000> >> > Suggestions on a soloution?> >> > --> > Posted via http://www.ruby-forum.com/.>> class Integer>   def to_roman>     "I =1       V =5      X = 10       L = 50>     C = 100    D = 500   M = 1000".>     scan( / ([A-Z]) \s *= \s* (\d+) /x ).>     map{|letter,val|  [ letter, val.to_i ] }.>     sort_by{|a| -a.last}.>     inject( [ "", self ] ){|roman, pair|>       [ roman.first + pair.first * (roman.last / pair.last),>         roman.last % pair.last ] }.>     first>   end> end>>>


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