Starting counter from 0

I'm working on a sheet of exercises using LaTeX. I've set up my sections to look like Exercise # | <title>.

How can I force the section counter to start from 0, so that I can have an exercise 0 explaining how to set up a working environment.

I'm using the titlesec package to format my section headings. I've set \documentclass to article to avoid having a numbering that looks like Exercise 0.x.

Here is my current formatting:

\newcommand{\hsp}{\hspace{20pt}}
\titleformat{\section}
[hang]
{\huge\bfseries}
{Exercice \thesection\hsp\textcolor{gray}{|}\hsp}
{0pt}
{\large\bfseries}


You can set your counters to whatever you want with the command \setcounter{}{}.

% arara: pdflatex

\documentclass{article}
\usepackage{titlesec}
\usepackage{xcolor}
\usepackage{blindtext}
\newcommand{\hsp}{\hspace{20pt}}
%%% option 1
%\usepackage[T1]{fontenc}
%\usepackage{lmodern}
%\titleformat{\section}[hang]{\huge\bfseries}{Exercice \thesection\hsp\textcolor{gray}{|}\hsp}{0pt}{\large\bfseries}
%%% option 2
\titleformat{\section}[hang]{\huge\bfseries}{Exercice \thesection\hsp\textcolor{gray}{\textbar}\hsp}{0pt}{\large\bfseries}

\begin{document}
\setcounter{section}{-1}
\Blinddocument
\end{document}


• With T1 font encoding the | looks as it should be. – Manuel Jun 9 '15 at 11:17
• @LaRiFaRi With \textbar instead of | there won't be any encodiong problem at all (I think). – Svend Tveskæg Jun 9 '15 at 11:39