# Package PGF Math Error: Unknown operator c' or c@'

I'm using the TikZ package to make a flowchart. I'm getting the following error: Package PGF Math Error: Unknown operator c' orc@' (in '1c'). \node (in1) [input] {node};

I don't understand what the error is referring to. This is my code:

\usepackage{tikz}
\usetikzlibrary{shapes.geometric, arrows}

\tikzstyle{question} = [rectangle, minimum width=3cm, minimum height=1cm,text centered, draw=black]
\tikzstyle{diagnosis} = [rectangle, rounded corners, minimum width=3cm, minimum height=1cm, text centered, draw=black]
\tikzstyle{input} = [diamond, minimum width=3cm, minimum height=1c, text centered, draw=black]
\tikzstyle{arrow} = [thick,->,>=stealth]

\begin{tikzpicture}[node distance=2cm]

\node (in1) [input] {node};
\node (q1) [question, below of=in1] {Matches distractor node?};
\draw [arrow] (in1) -- (q1);

\end{tikzpicture}

• minimum height=1c should be minimum height=1cm, methinks... – Rmano Jun 28 '18 at 15:36
• Welcome to TeX.SX! It would be great to see when we see compilable code, starting with \documentclass and ending with \end{document}. – Bobyandbob Jun 28 '18 at 15:40
• off-topic but you may want to switch to the \tikzset syntax instead of \tikzstyle, e.g. \tikzset{arrow/.style = {thick,->,>=stealth}}. – user121799 Jun 28 '18 at 15:40

You have a typo in the input style. You have minimum height=1c. I think you mean minimum height=1cm:

\tikzstyle{input} = [diamond, minimum width=3cm, minimum height=1cm, text centered, draw=black]


Also, as Mr. marmot said, the \tikzstyle syntax is somewhat discouraged and should be replaced by \tikzset:

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{shapes.geometric, arrows}

\tikzset{%
question/.style={rectangle, minimum width=3cm, minimum height=1cm,text centered, draw=black},
% \tikzstyle{question} = [rectangle, minimum width=3cm, minimum height=1cm,text centered, draw=black]
diagnosis/.style={rectangle, rounded corners, minimum width=3cm, minimum height=1cm, text centered, draw=black},
% \tikzstyle{diagnosis} = [rectangle, rounded corners, minimum width=3cm, minimum height=1cm, text centered, draw=black]
input/.style={diamond, minimum width=3cm, minimum height=1cm, text centered, draw=black},
% \tikzstyle{input} = [diamond, minimum width=3cm, minimum height=1cm, text centered, draw=black]
arrow/.style={thick,->,>=stealth}
% \tikzstyle{arrow} = [thick,->,>=stealth]
}

\begin{document}
\begin{tikzpicture}[node distance=2cm]

\node (in1) [input] {node};
\node (q1) [question, below of=in1] {Matches distractor node?};
\draw [arrow] (in1) -- (q1);

\end{tikzpicture}
\end{document}


I kept the previous syntax for comparison.

• You are right. I feel very stupid now. – Renate Jun 28 '18 at 15:38
• @Renate No worries, this happens for everyone :) – Phelype Oleinik Jun 28 '18 at 16:28