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A Lisp program for computing the Factorial of any given number in Linear Recursive or in Linear Iterative Process. Try both and notice the difference.
#lang racket
;;;;Linear Recursion and Iteration
;;;Linear Recursive process for computing factorials (fact-r n)
(define (fact-r n)
(if (= n 1)
1
(* n (fact-r (- n 1)))))
;;;Linear Iterative process for computing factorials (fact-i n)
(define (fact-i n)
(factorial-iterative 1 1 n))
(define (factorial-iterative product counter n)
(if (> counter n)
product
(factorial-iterative (* counter product)
(+ counter 1)
n)))
;Try using both process to get the factorial of large numbers as 999999;
;The program runs out of memory with (fact-r) but never with (fact-i),
;because with the Iterative process only 3 variables are being hold by the system,
;while in the Recursive process all the results of all the factorial calculations is being kept in memory.
;;In general, an iterative process is one whose state can be summarized by a fixed number of state variables,
;;together with a fixed rule that describes how the state variables should be updated as the process moves from state to state
;;and an (optional) end test that specifies conditions under which the process should terminate.
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