[Latex]ifhen 宏包的使用

[Latex]ifhen 宏包的使用提供了两个强大的判断条件:

\ifthenelse{判断条件}{肯定结构}{否定结构}

\whiledo{判断条件}{while语句}

\documentclass{article}
\usepackage{ifthen}\begin{document}\newcommand{\oddeven}[1]{Number #1 is %
\ifthenelse{\isodd{#1}}{odd}{even}  }
\oddeven{4}.\\ 
\oddeven{5}\newcounter{MYctr}
\whiledo{\value{MYctr}<5}%
{ ~\LaTeX~  %
\stepcounter{MYctr}}\end{document} 

下面的例子,使用循环判断来实现PDF动画的例子:

\documentclass[10pt]{beamer}\usepackage[utf8]{inputenc} \usepackage{color}
\usepackage{tikz}
\usepackage{hyperref}
\hypersetup{pdfpagemode=FullScreen}
\usepackage{ifthen}
\usepackage{animate}
%
\usetheme{Warsaw} 
\usecolortheme{whale}
%\begin{document}
%
\newcounter{m}
\setcounter{m}{0}
\newcounter{mc}
%
\begin{frame}[fragile]{Animated Integral}
\begin{center}
\begin{animateinline}[loop, poster = first, controls, palindrome]{2}
\whiledo{\them < 21}{\begin{tikzpicture}[scale=1.25]\draw[red,thick,<->] (-1,1) parabola bend (0,0) (2.1,4.41)node[below right] {$y=x^2$};\draw[loosely dotted] (-1,0) grid (4,4);%\path[use as bounding box] (-2,-1) rectangle (5,5);\draw[->] (-0.2,0) -- (4.25,0) node[right] {$x$};\draw[->] (0,-0.25) -- (0,4.25) node[above] {$y$};\setcounter{mc}{\value{m}*\value{m}}\shade[top color=blue,bottom color=gray!50](0,0) parabola (0.1*\them,0.01*\themc) |- (0,0);\end{tikzpicture}%\stepcounter{m}\ifthenelse{\them < 21}{\newframe}{\end{animateinline}\relax % BREAK}
} % END \whiledo...
\end{center}
\end{frame}
%
\end{document}

其实tikz也提供了一个函数ifthenelse(x,y,z),实现同样的功能.记住这和命令\ifthenelse是有区别的.