TeX use algorithm

tex

# for texlive 2017
$ tlmgr option repository ftp://tug.org/historic/systems/texlive/2017/tlnet-final && \
$ tlmgr install algorithms

\usepackage{algorithm,algorithmic}

example

\begin{algorithm}[H]
    \caption{配列から最大値を求める関数}
    \label{alg-max-from-array}
    \begin{algorithmic}[1]
        \Function{max\_in\_array}{$array$}
        \State $max \gets 0$
        \ForAll {$element \gets array$}
        \If {$element > max$}
        \State $max \gets element$
        \EndIf
        \EndFor
        \State \Return $max$
        \EndFunction
    \end{algorithmic}
\end{algorithm}
 
\ref{alg-max-from-array} です