# How to remove Overfull \hbox (12.0pt too wide) in paragraph at lines 11--11 []

\documentclass[10pt,twocolumn]{article}
\usepackage{graphicx}
\usepackage{amsmath}
\newcommand{\Keywords}[1]{\par\noindent
{\small{\em Keywords\/}: #1}}
\title{strong text}
\author{ \and
\centerline{Department of Computer Engineering,College of engineering,city}}
\date{}
\begin{document}

\maketitle
\begin{abstract}

• Note that you can mark text as 'code' by using indenting each line by four spaces. I tried to edit your code, but there are two problems that remain: (i) it is incomplete; (ii) lines 11-11 are blank, so I'm not fully convinced this code is the code causing the problems (or I edited it wrongly). – jon Jan 13 '17 at 5:07
• Who taught you to use \centerline there? Please reprimand them. – Martin Schröder Jan 13 '17 at 6:28

There is no need for \centerline within the \author declaration, since the \author - set as part of \maketitle - is already centred. So, remove it (and the seemingly superfluous \and):

\documentclass[twocolumn]{article}

\title{strong text}
\author{Department of Computer Engineering, College of Engineering, City}

\begin{document}

\maketitle

\begin{abstract}
Some abstract
\end{abstract}

\end{document}