If you want the entire \opening
to be centred, then the following redefinition of \@tablebox
works:
\makeatletter
\def\@tablebox#1{\begin{tabular}[t]{@{}c@{\extracolsep{\fill}}}#1\end{tabular}}
\makeatother
The original \@tablebox
used a l
eft-aligned column:
%\let\latexnofiles\nofiles % If you're using references in your resume
%\let\nofiles\relax % See https://tex.stackexchange.com/a/94528/5764
\documentclass[11pt]{res} % default is 10 pt
%\usepackage{helvetica} % uses helvetica postscript font (download helvetica.sty)
%\usepackage{newcent} % uses new century schoolbook postscript font
\usepackage{latexsym} % to get the \Box symbol
\setlength{\textheight}{10in} % increase text height to fit resume on 1 page
\topmargin=-0.5in % start text higher on the page
\makeatletter
\def\@tablebox#1{\begin{tabular}[t]{@{}c@{\extracolsep{\fill}}}#1\end{tabular}}
\makeatother
\begin{document}
\name{ANDREW J.\ MALONE}
\address{739 Mill Grove Drive \\ Audubon, PA 19403 \\ (215) 555-2216}
\opening
\end{document}
Alternatively, if you wish to have a left-aligned address with your name, use
\makeatletter
\def\@tablebox#1{%
\setbox9=\hbox{\namefont\@name}%
\begin{tabular}[t]{@{}p{\wd9}@{\extracolsep{\fill}}}#1\end{tabular}}
\makeatother
This is a very particular solution to your current setup. A more general solution would be required where the name length and font size could vary. However, without more detail, this should be sufficient.
%\let\latexnofiles\nofiles % If you're using references in your resume
%\let\nofiles\relax % See https://tex.stackexchange.com/a/94528/5764
\documentclass[11pt]{res} % default is 10 pt
%\usepackage{helvetica} % uses helvetica postscript font (download helvetica.sty)
%\usepackage{newcent} % uses new century schoolbook postscript font
\usepackage{latexsym} % to get the \Box symbol
\setlength{\textheight}{10in} % increase text height to fit resume on 1 page
\topmargin=-0.5in % start text higher on the page
\makeatletter
\def\@tablebox#1{%
\setbox9=\hbox{\namefont\@name}%
\begin{tabular}[t]{@{}p{\wd9}@{\extracolsep{\fill}}}#1\end{tabular}}
\makeatother
\begin{document}
\name{ANDREW J.\ MALONE}
\address{739 Mill Grove Drive \\ Audubon, PA 19403 \\ (215) 555-2216}
\opening
\end{document}
On a side note: res
removes the capability to use references within your document. See Problem using etaremune
(reversing the labels of items in a list) for an associated problem and fix for this.
Also, there is no particular need to use the res
class for creating a resume. It is possible to use the default article
class to replicate the layout, yet have some additional freedom in terms of the layout. Moreover, moderncv
provides a stylish take on resumes as well.