Roman Numerals Kata - in C++ - yay!

Epic: Convert Roman numerals to everyday Arabic integers

As an elementary school teacher, I want my students to be able to check their homework with an app that converts Roman numerals to Arabic integers, up to a maximum value of 4999.

###Acceptance criteria:

We’ll agree it’s done when...

• invalid Roman numeral combinations are handled (IIII is not 4, VIIII is not 9, IM is not 999, LL is not 100, DM, CMCD, ...keep going...)
• the valid range is 1 - 4999

1) Convert single-digit Roman numerals

As an elementary school teacher, I want to convert base Roman numerals to Arabic (I=1, V=5, X=10, L=50, C=100, D=500, M=1000)

2) Add Roman numerals

As an elementary school teacher, I want to add Roman numerals (e.g., II, III, VI, VII, VIII, XI, XII, XIII, LX)

3) Subtract Roman numerals

As an elementary school teacher, I want to subtract Roman numerals (e.g., IV, IX, XC, XL, CD)

4) Add and subtract Roman numerals in the same number

As an elementary school teacher, I want to comingle addition and subtraction of Roman numerals (e.g., XLVI=46, XCVIII=98, CDXLVI=446, MCMXCVIII=1998)

5) Handle invalid inputs

As an elementary school teacher, I want to handle invalid input strings (e.g., A, B, E, F, G, H, “”)