I'm working on a project where we're performing monthly date arithmetic: adding $n$ months to an initial month $m_1$ to obtain a resulting value of 1 through 12.
The standard modulo operation, $m_2$ = ($m_1 + n$) mod 12, will return the remainder $m_2$ = 0 rather than 12 if $m_1 + n$ = 12.
It's easy to redefine "0" as "12" with an if-then function in any programming language. But is there a more elegant way to perform a modulo operation that returns values of 1 - 12 rather than 0 - 11?