\newcommand{\point}[2]{
  \node [label=above:$#1$] (#1) at #2 {};
}

\begin{tikzpicture}[]
  \begin{scope}[every node/.style={fill=black, shape=circle, inner sep=1pt}]
    \point{a}{(0,0)}
    \point{b}{(1,0)}
    \point{c}{(2,0)}
  \end{scope}

  \draw (a) -- (b) -- (c);

\end{tikzpicture}