Math & Science ⇒ Recommend an \ifnum introduction

[LaTexLearner]

Can anybody recommend an introduction to the \ifnum commands?

I can't make sense of code that has them but I'd like to learn how they work.

Thanks!

[cgnieder]

\ifnum is a TeX primitive conditional for comparing integers:

Code: Select all

Code, edit and compile here:

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\ifnum1=1
  true
\else
  false
\fi % yields true
\ifnum1<2
  true
\else
  false
\fi % yields true
\ifnum1>2
  true
\else
  false
\fi % yields false
\bye
 
 
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Run LaTeX here

\ifnum and all other primitives are explained in the TeX book or in TeX by topic: texbytopic.

Regards

[Stefan Kottwitz]

Perhaps you may also be interested in the ifthen package.

Also, some modern packages such as pgf provide tools for comparing or calculating. More complex calculations could be done using LuaTeX. I use LuaTeX and binary math for calculating subnet IP addresses, for example.

Stefan