I tried to define \th to put the letters "th" in superscript for ordinal numbers. LaTeX tells me that \th is already defined. How is it defined? Would it be really bad to redefine it?
[Tex/LaTex] “Command \th already defined.”
macros
Related Solutions
What's apparently happening is the following: as @Ulrike remarks, your \newenvironment lacks its two mandatory arguments. It will instead pick up \newcounter and definition, since that is what follows.
What this does is that when you call \begin{definition}, you inadvertently call \newcounter, so
\begin{definition} The thing
turns into, with some technicalities omitted,
\newcounter The thing
i.e.
\newcounter{T}he thing
and that's where your counters come from and that's why you get an error: you probably have to definitions that start with "T"!
(To backtrack and solve your problem: I think you really mean to look at the amsthm package and its \newtheorem command?)
There are two \newcounter calls inside the macro \pichart.
When the macro is called the second time, then the counters are already defined and you get the error messages about already defined commands \c@a and \c@b, which are the internal command representation of the counters.
Move the \newcounter calls outside and reset the counters inside the macro:
\newcounter{a}
\newcounter{b}
\newcommand*{\piechart}[1]{%
\setcounter{a}{0}%
\setcounter{b}{0}%
...
}
Full example for completeness (and with larger fonts):
\documentclass{article}
\usepackage{calc}
\usepackage{ifthen}
\usepackage{tikz}
\usepackage{verbatim}
\newcommand{\piepart}[5]
{
\draw[thick,fill=#4] (0,0) -- (#1:1) arc (#1:#2:1) -- cycle;
\pgfmathparse{0.5*#1+0.5*#2}
\let\midangle\pgfmathresult
\pgfmathtruncatemacro{\trunc}{\midangle}
\ifthenelse{\trunc < 90}{
\draw (\midangle:1) node[above right]{#3};
}
{
\ifthenelse{\trunc < 180}{
\draw (\midangle:1) node[above left]{#3};
}
{
\ifthenelse{\trunc < 270}{
\draw (\midangle:1) node[below left]{#3};
}
{
\draw (\midangle:1) node[below right]{#3};
}
}
}
\pgfmathparse{min((#2-#1-10)/110*(-0.3),0)}
\let\temp\pgfmathresult
\pgfmathparse{max(\temp,-0.5) + 0.8}
\let\innerpos\pgfmathresult
\node at (\midangle:0.8) {#5};
}
\newcounter{a}
\newcounter{b}
\newcommand{\piechart}[1]
{
\setcounter{a}{0}%
\setcounter{b}{0}%
\foreach \p/\mcolor/\mname in #1
{
\setcounter{a}{\value{b}}
\addtocounter{b}{\p}
\piepart{\thea/100*360}
{\theb/100*360}
{\mname}{\mcolor}{\p\%}
}
}
\begin{document}
\begin{tikzpicture}[scale=1.5]
\tikzstyle{every node}=[font=\footnotesize]
\piechart{{75/gray/A, 18/green/B, 7/red/C}}
\end{tikzpicture}
\begin{tikzpicture}[scale=1.5]
\tikzstyle{every node}=[font=\footnotesize]
\piechart{{75/gray/A, 18/green/B, 7/red/C}}
\end{tikzpicture}
\end{document}
Best Answer
If you run
you get
\this defined in the kernel asand produces the
thorn(a letter in the Old English, Gothic, Old Norse and modern Icelandic alphabets, as well as some dialects of Middle English.)Yes, it's in general a bad idea to redefine an already defined macro and even more a kernel one (with the possible exception, in some cases, that you know exactly what you are doing and why you are doing it); that's why
\newcommand(unlike\def) checks to see first if the command is already defined. I'd suggest you to choose another name for your command (\Th, for example).If you, however, insist on redefining
\th(let's say you consider that you won't need the thorn and you are sure that your redefinition won't have undesired effects beyond suppressing access to the thorn), at least I'd suggest you to save the original definition first:In your particular case, place "th" for ordinals, you could use the
fmtcountpackage: