\documentclass{article}
\usepackage{clrscode3e}
\begin{document}
	\title{2.1-3}
	\author{pezy}
	\maketitle
	\begin{codebox}
		\Procname{$\proc{Linear-Search}(A, v)$}
		\li \For $j \gets 1$ \To $\attrib{A}{length}$
		\li		\Do
					\If $A[j] \isequal v$
		\li				\Then \Return $j$
		\li			\Else
						\Return \const{nil}
				\End
	\end{codebox}
\end{document}