
\documentclass{article}
\usepackage{lmodern}
\usepackage{listings}
\lstset{language=C}
\begin{document}
\thispagestyle{empty}
\begin{lstlisting}
#include <stdio.h>

int main(int argc, char ** argv)
{
  printf("Hello world!\n");
  return 0;
}
\end{lstlisting}
\end{document}
