Easiest way to center tables and other elements? - latex

Question

What is the best way to make things center properly? Once I start messing around with tables, things either start shifting left or right, destroying the balance. How can make it so everything is always centered?
Right now this will lead to the table being messed up, and have the right edge go off the screen. What can I do?
Here's most of the code, I cut out a lot of the useless functions, since they are all almost the same. Its for making Use Cases for school, since we got to do about 40 of these for a project.
\documentclass[10pt, a4paper]{article}
\usepackage{booktabs}
\begin{document}
\newcommand{\UCStart}[2]{
\newpage
\subsection[UC.#1]{UC.#1}
\begin{tabular}{|l|m{4in}|c|}
\hline
\textbf{UC.#1}
& \textbf{#2}
& \textbf{Traceability} \\ \hline
}
\newcommand{\UCDesc}[2]{
\textbf{Description}
& #1
& #2 \\ \hline
}
\newcommand{\UCActors}[2]{
\textbf{External Actors}
& #1
& #2 \\ \hline
}
% Snip... 40 odd more functions %
\newcommand{\UCEnd}{
\end{tabular}
}
\begin{table}[!ht]
\setlength{\extrarowheight}{2pt}
% UC 1
\UCStart{01}{Administrator Starts Server}
\UCDesc{This describes the process of the administrator starting the server}{\space}
\UCActors{Administrator}{\space}
\UCRelated{UC.02}{\space}
\UCPre{Server is not running}{\space}
\UCTrigger{Administrator wants to start the server}{\space}
\UCSeq{
\begin{enumerate}
\item Administrator boots up hardware
\item Administrator starts Administrator console
\item Administrator logins into Administrator account with the corresponding password
\item Administrator clicks start
\end{enumerate}
}{\space}
\UCPost{Conditions that must be true, in order for the use case to finish}{\space}
\UCAltSeq{
\textbf{Alternative Use Case 01} \newline
\begin{itemize}
\item UC.01.ALT.01
\item If administrator fails authentication in step 3
\begin{enumerate}
\item Notify administrator of failed authentication
\end{enumerate}
\end{itemize}
}{\space}
\UCNonFunc{ ??? }{\space}
\UCComments{ Comments Go Here }{\space}
\UCEnd
\end{table}
\end{document}

Answer 1

I can't compile your example due to several errors, and I'm not sure what you mean by "the best way to make things center properly". As a kind of crystal ball-type answer, is this what you're looking for?
\documentclass[10pt,a4paper]{article}
\usepackage{array}
\begin{document}
\begin{table}
\centering
\begin{tabular}{
| >{\centering\arraybackslash }p{4cm} |
>{\centering\arraybackslash }p{6cm} |
}
\hline
some centred text in cells & some more centred text in cells \\
\hline
centred text in cells & more centred text in cells \\
\hline
\end{tabular}
\end{table}
\end{document}

Answer 2

It is difficult to see what the problem is when we can't compile your example.
Looking through the code you provided, a table may not actually be appropriate in this situation. Instead, you might try something like the following:
\documentclass[10pt,a4paper]{article}
\begin{document}
\subsection{Administrator Starts Server}
\paragraph{Description:} This describes the process of the adminsitrator starting the server.
\paragraph{Actors:} Administrator
\paragraph{Preconditions:} Server is not running.
\paragraph{Sequence:}
\begin{enumerate}
\item Administrator boots up hardware
\item Administrator starts Administrator console
\item Administrator logins into Administrator account with the corresponding password
\item Administrator clicks start
\end{enumerate}
\end{document}
In the example you provided, I don't see that you ever put any text in the "Traceability" column. To mimic this column, you could either use \marginpar{my text} to put text in the margin, or you could use blahblah\hfill{}my text to right-align text on the same line as "blahblah". If you want the traceability text to be right-aligned and on its own line, use \begin{flushright} my text \end{flushright}.
If this doesn't help solve your problem, please provide us with a minimal example that compiles and demonstrates the problem.