Multiple columns with minipage, can't use 100% of \textwidth

Question

In a document I'm making, I have several cases where I need to organize things into several "columns." For example, here is some code I might use:

\documentclass[letterpaper,12pt]{report}

\usepackage[margin=1in]{geometry}

\begin{document}

\bigskip
\noindent
\begin{minipage}[t]{.45\textwidth}
\raggedright
This is \\
some left-aligned \\
text in a column \\
for demo purposes
\end{minipage}
\hfill
\noindent
\begin{minipage}[t]{.45\textwidth}
\raggedleft
This is \\
some different \\
text, right-aligned \\
for demo purposes, \\
and with more lines.
\end{minipage}

\end{document}

My question is concerning the {.45\textwidth} portion of the definition of the minipage environments. In my first attempt to setup this layout, I used the perhaps more intuitive {.5\textwidth} value on each of them - since I want to use up the entire page, splitting it in half.

However, when I use this value, I get a warning back from TeX:

Overfull \hbox (2.61107pt too wide) in paragraph at lines 8--28

What I'm wondering is, is this behavior just due to the fact that minipage has some implicit padding which I have to deal with via fractions like 0.45, or is there some cleaner way to define this environment?

(Keep in mind, this example is simplified - in the actual document, I may need more than two columns, and the columns may be sized unevenly.)

Answer 1

No, minipage does not provide padding. It's your use of spurious spaces that is causing the problem. To correct for this, use % at the end of a line. Consider, for example:

\noindent
\begin{minipage}[t]{.5\textwidth}
\raggedright
This is \\
some left-aligned \\
text in a column \\
for demo purposes
\end{minipage}% <---------------- Note the use of "%"
\begin{minipage}[t]{.5\textwidth}
\raggedleft
This is \\
some different \\
text, right-aligned \\
for demo purposes, \\
and with more lines.
\end{minipage}

Perhaps something that might be of use that provides some padding similar to that of a twocolumn document is to use a minipage width of \dimexpr.5\textwidth-.5\columnsep.

Here is a visual of the methods discussed to see the difference (I've added frames using \fbox with a zero-width gap/separation):

\documentclass[letterpaper,12pt]{report}

\usepackage[margin=1in]{geometry}
\setlength{\fboxsep}{-\fboxrule}% Just for this example
\begin{document}

\noindent
\fbox{\begin{minipage}[t]{.45\textwidth}
\raggedright
This is \\
some left-aligned \\
text in a column \\
for demo purposes
\end{minipage}}
\hfill
\noindent
\fbox{\begin{minipage}[t]{.45\textwidth}
\raggedleft
This is \\
some different \\
text, right-aligned \\
for demo purposes, \\
and with more lines.
\end{minipage}}

\bigskip

\noindent
\fbox{\begin{minipage}[t]{.5\textwidth}
\raggedright
This is \\
some left-aligned \\
text in a column \\
for demo purposes
\end{minipage}}
\hfill
\noindent
\fbox{\begin{minipage}[t]{.5\textwidth}
\raggedleft
This is \\
some different \\
text, right-aligned \\
for demo purposes, \\
and with more lines.
\end{minipage}}

\bigskip

\noindent
\fbox{\begin{minipage}[t]{\dimexpr.5\textwidth-.5\columnsep}
\raggedright
This is \\
some left-aligned \\
text in a column \\
for demo purposes
\end{minipage}}% <---------------- Note the use of "%"
\fbox{\begin{minipage}[t]{\dimexpr.5\textwidth-.5\columnsep}
\raggedleft
This is \\
some different \\
text, right-aligned \\
for demo purposes, \\
and with more lines.
\end{minipage}}

\end{document}