Why cannot the word in the last column be centered

Question

I have the following table:

\begin{tabular}{|p{3cm}|p{1.5cm}|p{1.5cm}|p{1.5cm}|p{1.5cm}|}
\hline
\centerline {image}
 &    \multicolumn{2}{c|}{ABC} & \multicolumn{2}{c|}{DEF} \\
\hline
 & \centering A&\centering B&\centering C&\centering D
 \\
\hline
\centerline 1&&&& \\
\hline
\centerline 1&&&& \\
\hline
\centerline 1&&&& \\
\hline
\centerline 1&&&& \\
\hline
\end{tabular}

When I try centering D, I have a problem in the shape of the table. Why is that? How can I center it appropriately?

Thanks.

Answer 1

Don't use the PlainTeX \centerline macro in a LaTeX document.

If the contents of every single column should be typeset centered, it's better to define column types that do so automatically, without the user having to type lots and lots of \centering instructions. This idea is implemented in the example below.

By the way, the user guide of the array package explains that there are some deep deep reasons for why ordinary \centering instructions need not work always correctly in the final column of a table. The package also suggests a workaround, which involves providing the instruction \arraybackslash.

\documentclass{article}
\usepackage{array}
\newcolumntype{U}{>{\centering\arraybackslash}p{3cm}}
\newcolumntype{V}{>{\centering\arraybackslash}p{1.5cm}}
\begin{document}
\begin{tabular}{|U|V|V|V|V|}
\hline
image & \multicolumn{2}{c|}{ABC} & \multicolumn{2}{c|}{DEF} \\
\cline{2-5}
 &  A& B& C& D \\
\hline
 1&&&& \\
\hline
 1&&&& \\
\hline
 1&&&& \\
\hline
 1&&&& \\
\hline
\end{tabular}
\end{document}

Answer 2

Using array package would enable you to simplify the markup a bit, nut you can do

\begin{tabular}{|p{3cm}|p{1.5cm}|p{1.5cm}|p{1.5cm}|p{1.5cm}|}
\hline
\centering {image}
 &    \multicolumn{2}{c|}{ABC} & \multicolumn{2}{c|}{DEF} \tabularnewline
\hline
 & \centering A&\centering B&\centering C&\centering D
 \tabularnewline
\hline
\centering 1&&&& \tabularnewline
\hline
\centering 1&&&& \tabularnewline
\hline
\centering 1&&&& \tabularnewline
\hline
\centering 1&&&& \tabularnewline
\hline
\end{tabular}

\tabularnewline and \\ normally mean the same thing in tables, but \tabularnewline is there even when \centering redefines \\ (and it was added for that reason).

Answer 3

If you are using \multicolumn, why not to use it for centering? And no \centerline's! They mean centered lines, so using them inside a tabular is strange.

A version without additional packages:

\documentclass{article}

\begin{document}

\begin{tabular}{|p{3cm}|p{1.5cm}|p{1.5cm}|p{1.5cm}|p{1.5cm}|}
\hline
%\centerline {image}
\centering image
 &    \multicolumn{2}{c|}{ABC} & \multicolumn{2}{c|}{DEF} \\
\hline
& \centering A&\centering B&\centering C& \multicolumn{1}{c|}{ D} \\
\hline
%\centerline 1&&&& \\
\centering 1&&&& \\
\hline
%\centerline 1&&&& \\
\centering 1&&&& \\
\hline
%\centerline 1&&&& \\
\centering 1&&&& \\
\hline
%\centerline 1&&&& \\
\centering 1&&& &\\
\hline
\end{tabular}
\end{document}