Problem Statement

Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero.

In Roman numerals:

Let's start with the solution:

\def\upperroman#1{\uppercase\expandafter{\romannumeral#1}}
Anno Domini \upperroman{\year}
\bye