How to use figures with latex correctly

Question

I used the following tags to put a figure in my latex in which to has 2 figures a and b and to appear as one figure behind each other :

\begin{figure}[ht]
\centering
\resizebox{\textwidth}{!}{%
\begin{tabular}{c c}
\includegraphics[width=2.0in] {fig1} &
\includegraphics [width=2.0in]{fig2} \\
\tiny   a. Pure Aloha & \tiny  b.~~ Slotted Aloha
\end{tabular}}
\centering
\caption{Comparision between pure Aloha and slotted Aloha and how they affected by the delay \cite{ahn2011design}}
\label{fig:1}
\end{figure}

But I got the text appeared above the image in my IEEE format as in this image:

Any suggestions ??

Answer 1

You have to use figure*, not figure. But there are other aspects in your code that should be taken care of.

It makes no sense to scale up something that's been scaled down by some unknown factor and then guess what the size of the subcaption be. Just scale the pictures to the right size to begin with. Here's an example:

\documentclass{IEEEtran}
\usepackage{graphicx}

\usepackage{lipsum} % just for the example

\begin{document}

\lipsum

\begin{figure*}
\centering

\begin{tabular*}{\textwidth}{@{\extracolsep{\fill}}c c cc}
&\includegraphics[width=.4\textwidth]{example-image-a} &
\includegraphics[width=.4\textwidth]{example-image-b} &\\
&a. Pure Aloha & b. Slotted Aloha &
\end{tabular*}

\caption{Comparison between pure Aloha and slotted Aloha and
         how they are affected by the delay \cite{ahn2011design}}
\label{fig:1}

\end{figure*}

\lipsum[1-15]

\end{document}

I use tabular* with four columns (the outer ones being empty) so the space can be automatically filled up at the sides and in the middle. There are other methods.

Answer 2

if you want to span the float in the both column, you should use

\begin{figure*}



\end{figure*}