FizzBuzz of first 100 numbers written using TeX macros. TeX is a very strange programming language, but hey it works...

fizzbuzz.tex

% Compile with pdftex, not pdflatex


\def\modulo#1#2{(#1-(#1/#2)*#2)}    % a mod n = a-(a/n)*n   where / is integer division

\newcount\X
\X=1
\loop
    \ifnum \numexpr\modulo{\X}{15} = 0
        FizzBuzz
    \else
        \ifnum \numexpr\modulo{\X}{3} = 0
            Fizz
        \else
            \ifnum \numexpr\modulo{\X}{5} = 0
                Buzz
            \else
                \the\X
            \fi
        \fi
    \fi
    \endgraf
    \advance \X by 1
    \unless \ifnum \X>100
    \repeat
\bye