I'm writing a document which will contain something like the image I included below. I don't want to use images because if I do, the document will contain a lot of images and I want to include this text in my LaTeX document the right way.
I don't know if this is possible, but can I have a section in latex, in which I can write whitespaces and tabs the way I do in a .txt document?
You can use the verbatim environment:
\begin{verbatim}
The verbatim environment
simply reproduces every
character you input,
including all s p a c e s!
\end{verbatim}
I'm not sure if tabs will do what you want; replace them by spaces if necessary.
An alternative to verbatim environment is to use a tabular-like environment, here's a sketch:
\documentclass{article}
\begin{document}
\begin{tabular}{*{14}{c}}
0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 & & & \\
e & i & n & - & t & e & s & t & e & s & t & & & \\
t & e & s & t & & & & & & & & & I=0 & j=0\\
& t & e & s & t & & & & & & & & I=1 & j=0\\
& & t & e & s & t & & & & & & & I=2 & j=0\\
& & & t & e & s & t & & & & & & I=3 & j=0\\
& & & & t & e & s & t & & & & & I=4 & j=1\\
& & & & & t & e & s & t & & & & I=5 & j=2\\
& & & & & & t & e & s & t & & & I=6 & j=3\\
& & & & & & & t & e & s & t & & I=7 & j=4\\
\multicolumn{14}{l}{Und dann wird j auf 1... }\\
& & & & & & & & t & e & s & t & I=8 & j=2\\
\end{tabular}
\end{document}
and its output.
In my opinion a tabular (or other table environment) here has the advantage that you can then configure spacing, font family and size, etc.