TeX/ifnum

概要

\ifnum <integer-1><R><integer-2> <tex-code-1> [\else <tex-code-2>] \fi

带有值

%A TeX primitive counter:
\newcount\countA%
\countA=5%

%A LaTeX counter:
\newcounter{counterB}%
\setcounter{counterB}{5}%

Lorem ipsum...
\makeatletter% c@<countername> can access the integer value of the counter. To use it, @ must be a letter
\ifnum\countA=\c@counterB\relax%
	Text tells you, that both counters are the same.\newpage
\else%
	No new page here. The counters are not the same.
\fi%
Lorem ipsum...

描述

\ifnum 命令表示一个if-then-else 控制结构的开始。<integer-1> 和 <integer-2> 必须扩展为整数，而 <R> 必须是字符 '=', '<' 或 '>' 之一。如果 <integer-1><R><integer-2> 扩展为真表达式，则处理 <tex-code-1>；否则忽略。如果包含 \else 部分，并且 <integer-1><R><integer-2> 扩展为假表达式，则处理 <tex-code-2>；否则忽略。