在下面的代码中，我们根据答案的长度以下列方式获取每个问题的答案 [1] (a) (b) (c) (d) 即 (4 列) [2] (a) (b) (c) (d) 即 (2 列)。很好....
这段代码中是否有任何更正，如果我想在一列中生成所有四个选项，我的意思是像（a）（b）（c）（d）（1 列）在我的问题库中有很多问题有一些长度合适的选项，并且不可能获得提到的 [1] 和 [2] 形式的输出。
请为该代码提供一些更好的解决方案，除了使用这个代码的几个问题之外，我几乎完成了我的工作。
\documentclass[12pt,a4paper]{exam}
\usepackage{amsmath,amsthm,amsfonts,amssymb,dsfont}
\setlength\parindent{0pt}
%usage \choice{ }{ }{ }{ }
%(A)(B)(C)(D)
\newcommand{\fourch}[4]{
\par
\begin{tabular}{*{4}{@{}p{0.23\textwidth}}}
(a)~#1 & (b)~#2 & (c)~#3 & (d)~#4
\end{tabular}
}
%(A)(B)
%(C)(D)
\newcommand{\twoch}[4]{
\begin{tabular}{*{2}{@{}p{0.46\textwidth}}}
(a)~#1 & (b)~#2
\end{tabular}
\par
\begin{tabular}{*{2}{@{}p{0.46\textwidth}}}
(c)~#3 & (d)~#4
\end{tabular}
}
%(A)
%(B)
%(C)
%(D)
\newcommand{\onech}[4]{
\par
(a)~#1 \par (b)~#2 \par (c)~#3 \par (d)~#4
}
\newlength\widthcha
\newlength\widthchb
\newlength\widthchc
\newlength\widthchd
\newlength\widthch
\newlength\tabmaxwidth
\setlength\tabmaxwidth{0.96\textwidth}
\newlength\fourthtabwidth
\setlength\fourthtabwidth{0.25\textwidth}
\newlength\halftabwidth
\setlength\halftabwidth{0.5\textwidth}
\newcommand{\choice}[4]{%
\settowidth\widthcha{AM.#1}\setlength{\widthch}{\widthcha}%
\settowidth\widthchb{BM.#2}%
\ifdim\widthch<\widthchb\relax\setlength{\widthch}{\widthchb}\fi%
\settowidth\widthchb{CM.#3}%
\ifdim\widthch<\widthchb\relax\setlength{\widthch}{\widthchb}\fi%
\settowidth\widthchb{DM.#4}%
\ifdim\widthch<\widthchb\relax\setlength{\widthch}{\widthchb}\fi%
\ifdim\widthch<\fourthtabwidth
\fourch{#1}{#2}{#3}{#4}
\else\ifdim\widthch<\halftabwidth
\ifdim\widthch>\fourthtabwidth
\twoch{#1}{#2}{#3}{#4}
\else
\onech{#1}{#2}{#3}{#4}
\fi
\fi\fi
}
\begin{document}
\begin{questions}
\question If $a = 3 + i$ and $z = 2 - 3i$ then the points on the Argand diagram
representing az, 3az and - az are
\choice{Vertices of a right angled triangle}{ Vertices of an equilateral
triangle}{Vertices of an isosceles triangle}{Collinear}
\question If z represents a complex number then $\arg (z) + \arg\left(\bar z\right)$ is
\choice{$\dfrac{\pi}{4}$}{$\dfrac{\pi}{2}$}{0}{$\dfrac{\pi}{6}$}
\question If the amplitude of a complex number is $\dfrac{\pi}{2}$ then the number is
\choice{ purely imaginary}{purely real}{0}{neither real nor imaginary}
\question The value of $i + i^{22} + i^{23} + i^{24} + i^{25}$ is
\choice{i}{-i}{1}{-1}
\question The volume generated by
rotating the triangle with vertices at
(0, 0), (3, 0) and (3, 3) about x-axis is
\choice{$18\pi$}{$2\pi$}{$36\pi$}{$9\pi$}\end{questions}
\end{document}
\end{document}
答案1
要获得单列答案，\ifdim需要稍微改变一下顺序。顺序应该是：如果最长答案适合 1/4，则放置四列，否则如果最长答案适合 1/2 宽度，则放置 2 列，否则放置 1 列。
此外，四个答案的长度分配不正确（b 用于 b、c 和 d）。MWE 进行了以下更正：
\documentclass[12pt,a4paper]{exam}
\usepackage{amsmath,amsthm,amsfonts,amssymb,dsfont}
\setlength\parindent{0pt}
%usage \choice{ }{ }{ }{ }
%(A)(B)(C)(D)
\newcommand{\fourch}[4]{
\par
\begin{tabular}{*{4}{@{}p{0.23\textwidth}}}
(a)~#1 & (b)~#2 & (c)~#3 & (d)~#4
\end{tabular}
}
%(A)(B)
%(C)(D)
\newcommand{\twoch}[4]{
\begin{tabular}{*{2}{@{}p{0.46\textwidth}}}
(a)~#1 & (b)~#2
\end{tabular}
\par
\begin{tabular}{*{2}{@{}p{0.46\textwidth}}}
(c)~#3 & (d)~#4
\end{tabular}
}
%(A)
%(B)
%(C)
%(D)
\newcommand{\onech}[4]{
\par
(a)~#1 \par (b)~#2 \par (c)~#3 \par (d)~#4
}
\newlength\widthcha
\newlength\widthchb
\newlength\widthchc
\newlength\widthchd
\newlength\widthch
\newlength\tabmaxwidth
\setlength\tabmaxwidth{0.96\textwidth}
\newlength\fourthtabwidth
\setlength\fourthtabwidth{0.25\textwidth}
\newlength\halftabwidth
\setlength\halftabwidth{0.5\textwidth}
\newcommand{\choice}[4]{%
\settowidth\widthcha{AM.#1}\setlength{\widthch}{\widthcha}%
\settowidth\widthchb{BM.#2}%
\ifdim\widthch<\widthchb\relax\setlength{\widthch}{\widthchb}\fi%
\settowidth\widthchc{CM.#3}%
\ifdim\widthch<\widthchc\relax\setlength{\widthch}{\widthchc}\fi%
\settowidth\widthchd{DM.#4}%
\ifdim\widthch<\widthchd\relax\setlength{\widthch}{\widthchd}\fi%
\ifdim\widthch<\fourthtabwidth
\fourch{#1}{#2}{#3}{#4}
\else\ifdim\widthch<\halftabwidth
\twoch{#1}{#2}{#3}{#4}
\else
\onech{#1}{#2}{#3}{#4}
\fi
\fi
}
\begin{document}
\begin{questions}
\question If $a = 3 + i$ and $z = 2 - 3i$ then the points on the Argand diagram
representing az, 3az and - az are
\choice{Vertices of a right angled triangle}{ Vertices of an equilateral
triangle}{Vertices of an isosceles triangle}{Collinear}
\question If z represents a complex number then $\arg (z) + \arg\left(\bar z\right)$ is
\choice{$\dfrac{\pi}{4}$}{$\dfrac{\pi}{2}$}{0}{$\dfrac{\pi}{6}$}
\question If the amplitude of a complex number is $\dfrac{\pi}{2}$ then the number is
\choice{ purely imaginary}{purely real}{0}{neither real nor imaginary}
\question The value of $i + i^{22} + i^{23} + i^{24} + i^{25}$ is
\choice{i}{-i}{1}{-1}
\question The volume generated by
rotating the triangle with vertices at
(0, 0), (3, 0) and (3, 3) about x-axis is
\choice{$18\pi$}{$2\pi$}{$36\pi$}{$9\pi$}
\question A question with very long answers
\choice{This answer is very long and will need the full width of the page to display which leads to a single column}{This answer, like the first, is very long and will need the full width of the page to display which leads to a single column}{This answer, like the second is very long and will need the full width of the page to display which leads to a single column}{This answer, like the third, is very long and will need the full width of the page to display which leads to a single column}
\end{questions}
\end{document}
请注意，您的 MWE 有两个\end{document}语句。
备注：问题不太清楚（我希望这个解决方案正是您所需要的）。为了便于将来参考，请提供一个出错的示例，在这种情况下，这是一个答案较长的问题。