Chapter 3, Problem 13PP

Roman numbers. Write a program that converts a positive integer into the Roman number system. The Roman number system has digits

Numbers are formed according to the following rules:

1. a. Only numbers up to 3,999 are represented.
2. b. As in the decimal system, the thousands, hundreds, tens, and ones are expressed separately.
3. c. The numbers 1 to 9 are expressed as

As you can see, an I preceding a V or X is subtracted from the value, and you can never have more than three I’s in a row.

1. d. Tens and hundreds are done the same way, except that the letters X, L, C and C, D, M are used instead of I, V, X, respectively.

Your program should take an input, such as 1978, and convert it to Roman numerals, MCMLXXVIII.