Numbers calculator: Roman and Arabic

You can calculate on your prefered numeral system separately (not simultaneously): Roman numbers or Arabic decimal numbers.

$ git clone https://github.com/proxy-m/RomeArabCalc
$ cd RomeArabCalc
$ cd ./src/main/java
$ javac quickstart/RomeArabCalc.java
$ javac quickstart/RomeArabCalcFloat.java

$ java -cp . quickstart.RomeArabCalc 'X-II'
$ java -cp . quickstart.RomeArabCalc '10-2'
$ java -cp . quickstart.RomeArabCalc 'X II'
$ java -cp . quickstart.RomeArabCalc 'X*II'
$ java -cp . quickstart.RomeArabCalc 'III^II' # pow(III, II)
$ java -cp . quickstart.RomeArabCalc '8 b 2' # log2(8)
$ java -cp . quickstart.RomeArabCalc 'X̅C̅MMDXXI ~ TOARAB'
$ java -cp . quickstart.RomeArabCalc '347 ~ TOARAB'
$ java -cp . quickstart.RomeArabCalc '19 ~ TOROMAN'
$ java -cp . quickstart.RomeArabCalc 'XIX ~ TOROMAN'
$ java -cp . quickstart.RomeArabCalc '92521 ~ TOROMAN'
$ java -cp . quickstart.RomeArabCalcFloat 103993.0 / 33102
$ java -cp . quickstart.RomeArabCalcFloat '3.1 ~ TOROMAN'
$ java -cp . quickstart.RomeArabCalcFloat '3.14 ~ TOROMAN'
$ java -cp . quickstart.RomeArabCalcFloat '3.141 ~ TOROMAN'
$ java -cp . quickstart.RomeArabCalcFloat '3.1415 ~ TOROMAN'
$ java -cp . quickstart.RomeArabCalcFloat '3.14159 ~ TOROMAN'
$ java -cp . quickstart.RomeArabCalcFloat 'IX/II'
$ java -cp . quickstart.RomeArabCalc 'IX/II'
$ java -cp . quickstart.RomeArabCalc 'IX%II'
$ java -cp . quickstart.RomeArabCalc 'II / III'
$ java -cp . quickstart.RomeArabCalcFloat 'II.iii * VII.iivx' # 2.3 * 7.71
$ java -cp . quickstart.RomeArabCalcFloat 'I.ii   VI.x' # 1.2   6.01
$ java -cp . quickstart.RomeArabCalcFloat '5.2   4.8'
$ java -cp . quickstart.RomeArabCalcFloat '5 - 8'

Java 8 JDK

• As of today following characters may be used in the Roman numeral system:

  • I = 1;
  • V = 5;
  • X = 10;
  • L = 50;
  • C = 100;
  • D = 500;
  • M = 1000.

• if the larger digit comes before the smaller one, they add up:

  • VI = 5 1 = 6;
  • XV = 10 5 = 15;
  • LX = 50 10 = 60;
  • CL = 100 50 = 150;

• if the smaller digit comes before the larger one (in which case it cannot be repeated), then the smaller one is subtracted from the larger one; only numbers representing 1 or powers of 10 can be subtracted; only the digit that is next in the number series to the one to be deducted may be reduced:

  • IV = 5 - 1 = 4;
  • IX = 10 - 1 = 9;
  • XL = 50 - 10 = 40;
  • XC = 100 - 10 = 90;

• digits V, L, D cannot be repeated; digits I, X, C, M may be repeated not more than 3 times in a row:

  • VIII = 8;
  • LXXX = 80;
  • DCCC = 800;
  • MMMD = 3500.

• A bar over a number increases its value by 1,000 times:

  • V̅ = 5000;
  • X̅ = 10000;
  • L̅ = 50000;
  • C̅ = 100000;
  • D̅ = 500000;
  • M̅ = 1000000.

• Basic Roman numerals

  • 1 = I
    2 = II
    3 = III
    4 = IV
    5 = V
    6 = VI
    7 = VII
    8 = VIII
    9 = IX
    10 = X
    20 = XX
    30 = XXX
    40 = XL
    50 = L
    60 = LX
    70 = LXX
    80 = LXXX
    90 = XC
    100 = C
    200 = CC
    300 = CCC
    400 = CD
    500 = D
    600 = DC
    700 = DCC
    800 = DCCC
    900 = CM
    1 000 = M
    2 000 = MM
    3 000 = MMM
    4 000 = MV̅ / I̅V̅
    5 000 = V̅
    6 000 = V̅M
    7 000 = V̅MM
    8 000 = V̅MMM
    9 000 = MX̅ / I̅X̅
    10 000 = X̅
    20 000 = X̅X̅
    30 000 = X̅X̅X̅
    40 000 = X̅L̅
    50 000 = L̅
    60 000 = L̅X̅
    70 000 = L̅X̅X̅
    80 000 = L̅X̅X̅X̅
    90 000 = X̅C̅
    100 000 = C̅
    200 000 = C̅C̅
    300 000 = C̅C̅C̅
    400 000 = C̅D̅
    500 000 = D̅
    600 000 = D̅C̅
    700 000 = D̅C̅C̅
    800 000 = D̅C̅C̅C̅
    900 000 = C̅M̅
    1 000 000 = M̅