Roman numerals/Encode: Difference between revisions
(→{{header|Java}}: Added support for CD as 400) |
(→{{header|Java}}: Error condition for negative numbers.) |
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{{trans|Ada}} |
{{trans|Ada}} |
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The helper function <tt>copies</tt> is added since Java does not support String multiplication. |
The helper function <tt>copies</tt> is added since Java does not support String multiplication. The conversion function returns <tt>null</tt> for a negative number, since Java does not have unsigned primitives. |
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<java>public class RN{ |
<java>public class RN{ |
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public static void main(String args[]){ |
public static void main(String args[]){ |
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} |
} |
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public static String roman(long n){ |
public static String roman(long n){ |
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if(n < 1) return null; |
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String result = ""; |
String result = ""; |
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if(n >= 1000){ |
if(n >= 1000){ |
Revision as of 03:21, 1 April 2008
You are encouraged to solve this task according to the task description, using any language you may know.
Create a function taking a positive integer as its parameter and returning a string containing the Roman Numeral representation of that integer.
Ada
<Ada> with Ada.Text_Io; use Ada.Text_Io; with Ada.Strings.Unbounded; use Ada.Strings.Unbounded;
procedure Roman_Numeral_Test is
function To_Roman(Number : Positive) return String is Result : Unbounded_String; Current_Value : Natural := Number; begin if Current_Value >= 1000 then Result := Result & ((Current_Value / 1000) * 'M'); Current_Value := Current_Value mod 1000; end if; if Current_Value >= 900 then Result := Result & "CM"; Current_Value := Current_Value mod 900; end if; if Current_Value >= 500 then Result := Result & "D"; Current_Value := Current_Value mod 500; end if; if Current_Value >= 100 then Result := Result & ((Current_Value / 100) * 'C'); Current_Value := Current_Value mod 100; end if; if Current_Value >= 90 then Result := Result & "XC"; Current_Value := Current_Value mod 90; end if; if Current_Value >= 50 then Result := Result & "L"; Current_Value := Current_Value mod 50; end if; if Current_Value >= 40 then Result := Result & "XL"; Current_Value := Current_Value mod 40; end if; if Current_Value >= 10 then Result := Result & ((Current_Value / 10) * 'X'); Current_Value := Current_Value mod 10; end if; if Current_Value = 9 then Result := Result & "IX"; Current_Value := 0; end if; if Current_Value >= 5 then Result := Result & "V"; Current_Value := Current_Value mod 5; end if; if Current_Value = 4 then Result := Result & "IV"; Current_Value := 0; end if; Result := Result & (Current_Value * 'I'); return To_String(Result); end To_Roman;
begin
Put_Line(To_Roman(1999)); Put_Line(To_Roman(25)); Put_Line(To_Roman(944));
end Roman_Numeral_Test; </Ada> Output:
MCMXCIX XXV CMXLIV
Java
The helper function copies is added since Java does not support String multiplication. The conversion function returns null for a negative number, since Java does not have unsigned primitives. <java>public class RN{ public static void main(String args[]){ System.out.println(roman(1999)); System.out.println(roman(25)); System.out.println(roman(954)); } public static String roman(long n){ if(n < 1) return null; String result = ""; if(n >= 1000){ result+= (copies("M",(n / 1000))); n%= 1000; } if(n >= 900){ result+= "CM"; n%= 900; } if(n >= 500){ result+= "D"; n%= 500; } if(n >= 400){ result+= "CD"; n%= 400; } if(n >= 100){ result+= (copies("C",(n / 100))); n%= 100; } if(n >= 90){ result+= "XC"; n%= 90; } if(n >= 50){ result+= "L"; n%= 50; } if(n >= 40){ result+= "XL"; n%= 40; } if(n >= 10){ result+= (copies("X",(n / 10))); n%= 10; } if(n == 9){ result+= "IX"; n= 0; } if(n >= 5){ result+= "V"; n%= 5; } if(n == 4){ result+= "IV"; n= 0; } result+= (copies("I",n)); return result; }
public static String copies(String a, int n){ String result = ""; for(int i= 0;i < n;i++,result+= a); return result; } }</java> Output:
MCMXCIX XXV CMXLIV