Converting between Roman Numerals and Arabic Numbers

Program to Converts between Roman Numerals and Arabic Numbers:

Generates Arabic Numbers when user types in Roman Numerals
Generates Roman Numerals when user types in Arabic Numbers

Establish Global variables
Define rn = a string of characters for Roman numeral input
Define rw = a string of characters for Roman numeral working storage
Define an = an integer for the Arabic number computed

Start-
Ask user to "Enter a Roman Numeral or an Arabic Number (Q to exit)"
Get number to convert from user as a string of characters rn
Convert rn to all uppercase characters
If rn contains a "Q" character then terminate the program
If the first character of rn >= "0" and <= "9" then
  Set an = the Arabic number given in rn
  Output "The Roman Numeral for " an "is "
  Call the subroutine AToR to convert an to rw
  Output rw
Else
  Set rw = rn
  Set an = 0
  While rw contains the substring "CM"
    Replace the found substring in rw with blanks
    Set an = an + 900
  While rw contains the substring "CD"
    Replace the found substring in rw with blanks
    Set an = an + 400
  While rw contains the substring "XC"
    Replace the found substring in rw with blanks
    Set an = an + 90
  While rw contains the substring "XL"
    Replace the found substring in rw with blanks
    Set an = an + 40
  While rw contains the substring "IX"
    Replace the found substring in rw with blanks
    Set an = an + 9
  While rw contains the substring "IV"
    Replace the found substring in rw with blanks
    Set an = an + 4
  While rw contains the substring "M"
    Replace the found substring in rw with blanks
    Set an = an + 1000
  While rw contains the substring "D"
    Replace the found substring in rw with blanks
    Set an = an + 500
  While rw contains the substring "C"
    Replace the found substring in rw with blanks
    Set an = an + 100
  While rw contains the substring "L"
    Replace the found substring in rw with blanks
    Set an = an + 50
  While rw contains the substring "X"
    Replace the found substring in rw with blanks
    Set an = an + 10
  While rw contains the substring "V"
    Replace the found substring in rw with blanks
    Set an = an + 5
  While rw contains the substring "I"
    Replace the found substring in rw with blanks
    Set an = an + 1
  Output "The Arabic Number for " rn " is " an
  Call the subroutine AToR to convert an to rw
  If rw equals rn then
    Output "The Roman Numeral is in the correct format"
  Else
    Output "The correct format for this is " rw
Start over for next input   

Subroutine AToR Converts from Arabic Number an to Roman Numeral rw
    Set rw = "" the zero length string
    WHILE an >= 1000
      Set rw = rw + "M" (add "M" to right end of rw)
      Set an = an - 1000
    If an >= 900 then Set rw = rw + "CM", Set an = an - 900   [0, 999]
    If an >= 500 then Set rw = rw + "D", Set an = an - 500    [0, 899]
    If an >= 400 then Set rw = rw + "CD", Set an = an - 400   [0, 499]
    WHILE an >= 100                                           [0, 399]
      Set rw = rw + "C"
      Set an = an - 100
    If an >= 90 then Set rw = rw + "XC", Set an = an - 90     [0, 99]
    If an >= 50 then Set rw = rw + "L", Set an = an - 50      [0, 89]
    If an >= 40 then Set rw = rw + "XL", Set an = an - 40     [0, 49]
    WHILE an >= 10                                            [0, 39]
      Set rw = rw + "X"
      Set an = an - 10
    If an >= 9 then Set rw = rw + "IX", Set an = an - 9       [0, 9]
    If an >= 5 then Set rw = rw + "V", Set an = an - 5        [0, 8]
    If an >= 4 then Set rw = rw + "IV", Set an = an - 4       [0, 4]
    WHILE an >= 1                                             [0, 3]
      Set rw = rw + "I"
      Set an = an - 1
 END of Subroutine AToR

Sample output:

Enter a Roman Numeral or an Arabic Number (Q to exit) 1995
The Roman Numeral for 1995 is MCMXCV

Enter a Roman Numeral or an Arabic Number (Q to exit) MCMXCV
The Arabic Number for MCMXCV is 1995
The Roman Numeral is in the correct format

Enter a Roman Numeral or an Arabic Number (Q to exit) xccmmv
The Arabic Number for XCCMMV is 1995
The correct format for this is MCMXCV

Enter a Roman Numeral or an Arabic Number (Q to exit) q

And: Roman numerals -- From Wikipedia, the free encyclopedia

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This page accessed times since April 6, 2005.
Page created by: hjsmithh@sbcglobal.net
Changes last made on Saturday, 25-Apr-09 07:22:15 PDT

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