[Solved] CS3723 HW #7 Python

Write two Python programs. One that converts a number to a Roman Numeral (roman.py), and the other converts it back to a number(namor.py). Each one should accept one or more values using sys.argv(1:).

For both programs, you MUST use a function to do the conversion. For roman.py, define a function that takes a number and returns the string. For namor.py, the function takes a string and returns a number.

You MUST submit code and some sample output for each (submit 2 .py files and 2 output files). Some comments should be present in your code (no fixed rules) and a little bit of discussion is encouraged.

1. Given a number, return a Roman Numeral string. (10 points)
2. Any number <= 0 or > 3,999, or invalid number, return Error.
3. Use only these standard values (wikipedia.org/wiki/Roman_numerals).
4. Assume the input is a number and not a string.

1 = I

2 = II

3 = III

4 = IV

5 = V

6 = VI

7 = VII

8 = VIII

9 = IX10 = 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 = CM1000 = M

2000 = MM

3000 = MMM

Examples:

74 = LXXIV

299 = CCXCIX

2019 = MMXIX

Examples:

roman.py 812 43 prints 812 is DCCCXII and 43 is XLIII

roman.py 49 5000 prints 49 is XLIX and 5000 is Error

Hints for Part I:

1. Look at thousands then hundreds then tens then ones.
2. Create 4 Lists and put for the zero values.

E.g., tens = [, X, XX, XXX, XL, L, , XC]

3. Use // for integer divide and % for remainder.

1. Given a Roman Numeral String, parse it and return the number. If it does not match a legal number from above (in the range 1 to 3,999), return -1. (20 points)

Examples:

namor.py CCCXIV prints CCCXIV is 314

namor.py MCMXCIX prints MCMXCIX is 1999

namor.py CXXXXI prints CXXXXI is -1

namor.py 123 MMMM II prints 123 is -1 and MMMM is -1 and II is 2

Hints for Part II:

1. Use 4 dictionaries instead of Lists. Use dict.items() method.

E.g., tens = {XC: 90, LXXX: 80, LXX: 70, , X: 10}

2. Very Important: Put each dictionary in reverse order

E.g., look for XC then LXXX then LXX then LX then L, etc.

3. Use the str.upper() and str.startswith() methods.