If $n,a\in\Bbb Z$ and $0<a<n$ then we know that $u\equiv n\bmod a$ iff $n=at+u$ holds for some $t\in\Bbb Z$.
Suppose $a=b+i$ where $i^2=-1$ what is $n\bmod a$ for cases $n\in\Bbb Z$ and when $n\in\Bbb Z[i]$?
Does it have interpretation of smallest remainder?