Personal counter is unintended reset after itemize environment [duplicate]

Question

This question already has an answer here:

• What are the differences between TeX counts and LaTeX counters? 1 answer

I created a counter named foo to add up so money which I want to get from my boss. When having an itemize environment the counter is reset accidently. Does anyone know why or how to solve problem (so tell my what I am doing wrong ;-) )? I added comment lines to clear up what I want to do. Everytime I add a value of money, the sum is created.

\documentclass{scrbook}
%\usepackage{eurosym}
%\newcommand{\eu}[1]{\advance\foo by #1 \EUR{#1}}
\begin{document}
Create Counter: \newcount\foo

Give counter: \the\foo

Increase by three: \advance\foo by 3

Give result: \the\foo

\begin{itemize}
    \item Increase by seven: \advance\foo by 7
    %\item \eu{7}
    \item Give result: \the\foo
\end{itemize}

Give result: \the\foo
\end{document}  

The PDF looks like:

Create Counter:

Give counter: 0

Increase by three:

Give result: 3

• Increase by seven:

• Give result: 10

Give result: 3

I use texniccenter with Miktex 2.9 on a Win7 64 machine.

Answer 1

These are TeX-core counters, which work locally. You would have to use \global\advance. However, I suggest using LaTeX counters, which are global by default:

\documentclass{scrbook}

\begin{document}
Create Counter: \newcounter{foo}

Give counter: \arabic{foo}

Increase by three: \addtocounter{foo}{3}

Give result: \arabic{foo}

\begin{itemize}
    \item Increase by seven: \addtocounter{foo}{3}
    \item Give result: \arabic{foo}
\end{itemize}

Give result: \arabic{foo}
\end{document}