为什么 Latex 不能识别我的子图？

Question

\documentclass[11pt,a4paper,twoside]{book}    
\usepackage{caption}    
\usepackage{subcaption}    
\usepackage{graphicx} % [demo] is just for the example

\begin{document}    

\begin{figure}[ht]   
\centering    
\subfloat[A bounded feasible region]{\includegraphics[width=0.3\textwidth, keepaspectratio]{2s3a.jpg}\label{fig:subfig5}}    
\subfloat[Unbounded feasible region]{\includegraphics[width=0.3\textwidth, keepaspectratio]{2s3b.jpg}\label{fig:subfig6}}    
\subfloat[Unbounded feasible region]{\includegraphics[width=0.3\textwidth, keepaspectratio]{2s3c.jpg}\label{fig:subfig7}}    
\caption[Optional caption for list of figures 5-8]{Feasible region}    
\label{fig:subfigureExample2}
\end{figure}

Reference to figure \ref{fig:subfigureExample2} and \ref{fig:subfig6}.

\end{document}

Answer 1

对于使用该包的我来说，此代码有效subfig。

\documentclass[11pt,a4paper,twoside]{book}    
\usepackage{caption}    
\usepackage{subfig}    
\usepackage[demo]{graphicx} % [demo] is just for the example    

\begin{document}    

\begin{figure}[ht]   
\centering
\subfloat[A bounded feasible region]{\includegraphics[width=0.3\textwidth, keepaspectratio]{2s3a.jpg}\label{fig:subfig5}}
\subfloat[Unbounded feasible region]{\includegraphics[width=0.3\textwidth, keepaspectratio]{2s3b.jpg}\label{fig:subfig6}}
\subfloat[Unbounded feasible region]{\includegraphics[width=0.3\textwidth, keepaspectratio]{2s3c.jpg}\label{fig:subfig7}}
\caption[Optional caption for list of figures 5-8]{Feasible region}
\label{fig:subfigureExample2}
\end{figure}

Reference to figure \ref{fig:subfigureExample2} and \ref{fig:subfig6}.

\end{document}

Answer 2

为了subcaption你需要不同的语法

\documentclass[11pt,a4paper,twoside]{book}    
%\usepackage{caption}    
\usepackage{subcaption}    
\usepackage[demo]{graphicx} % [demo] is just for the example    
\begin{document}    

\begin{figure}
\centering
\begin{subfigure}{0.3\textwidth}\Huge A\caption{A bounded feasible region}\label{fig:subfig5}\end{subfigure}
\begin{subfigure}{0.3\textwidth}\Huge B\caption{A bounded feasible region}\label{fig:subfig6}\end{subfigure}
\begin{subfigure}{0.3\textwidth}\Huge C\caption{A bounded feasible region}\label{fig:subfig7}\end{subfigure}
\caption[Optional caption for list of figures 5-8]{Feasible region}
\label{fig:subfigureExample2}
\end{figure}

Reference to figure: \ref{fig:subfigureExample2} and \ref{fig:subfig6}.

\end{document}

Answer 3

除了加载subfig包而不是subcaption包之外，您还应该提供一些代码来在图中三项之间提供空白。我建议您删除指令\centering并\hspace{\fill}在两个地方插入。

\documentclass[11pt,a4paper,twoside]{book}    
%\usepackage{caption}   %% not needed for this MWE  
\usepackage{subfig}    
\usepackage[demo]{graphicx} % [demo] is just for the example    
\begin{document}    

\begin{figure}[ht]   
\subfloat[A bounded feasible region]{\includegraphics[width=0.3\textwidth, keepaspectratio]{2s3a.jpg}\label{fig:subfig5}}
\hspace{\fill}
\subfloat[Unbounded feasible region]{\includegraphics[width=0.3\textwidth, keepaspectratio]{2s3b.jpg}\label{fig:subfig6}}
\hspace{\fill}
\subfloat[Unbounded feasible region]{\includegraphics[width=0.3\textwidth, keepaspectratio]{2s3c.jpg}\label{fig:subfig7}}

\caption[Optional caption for list of figures 5--8]{Feasible region}
\label{fig:subfigureExample2}
\end{figure}

Reference to figure \ref{fig:subfigureExample2} and \ref{fig:subfig6}.
\end{document}