1.33.tex

\documentclass[a4paper,12pt]{article}
\usepackage{listings}
\lstset{language=Lisp}

\begin{document}
\noindent
\begin{lstlisting}
(define (filtered-accumulate pred?
			     combiner
			     null-value
			     term
			     a
			     next
			     b)
  (define (iter a result)
    (cond ((> a b) result)
	  ((pred? a) (iter (next a)
			   (combiner (term a)
				     result)))
	  (else (iter (next a) result))))
  (iter a null-value))
\end{lstlisting}

\medskip \noindent
a. \lstinline!(filtered-accumulate prime? + square a inc b)!

\medskip \noindent
b.
\begin{lstlisting}
(filtered-accumulate (lambda (x)
		       (= (gcd x n) 1))
		     *
		     (lambda (x) x)
		     1
		     inc
		     (- n 1))
\end{lstlisting}
\end{document}