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RECURSIVE VERSION
global ________________________
env | other var. |
------->| factorial : * |
| | |
|_____________|_________|
| ^
| |
variables : n
body: (if (= n 1) 1 (* n (factorial (- n 1))))
(factorial 6)
_______ ^
E1 -->| n : 6 |___________| GLOBAL
-------
(* 6 (factorial 5))
_______ ^
E2 -->| n : 5 |___________| GLOBAL
-------
(* 5 (factorial 4))
_______ ^
E3 -->| n : 4 |___________| GLOBAL
-------
(* 4 (factorial 3))
_______ ^
E4 -->| n : 3 |___________| GLOBAL
-------
(* 3 (factorial 2))
_______ ^
E5 -->| n : 2 |___________| GLOBAL
-------
(* 2 (factorial 1))
_______ ^
E6 -->| n : 1 |___________| GLOBAL
-------
1
ITERATIVE VERSON
global ___________________________________
env | other var. |
------->| factorial : * |
| fact-iter : | * |
|_____________|_______________|____|
| ^ | ^
| | | |
| | variable : (product counter max-count)
| | body: (if (> counter max-count)
| | prod
| | (fact-iter (* counter product)
| | (+ counter 1)
| | max-count))
| |
variable: n
body: (fact-iter 1 1 n)
(factorial 6)
_______ ^
E1 -->| n : 6 |_____________| GLOBAL
-------
(fact-iter 1 1 n)
E2 -->| product : 1 ^
| counter : 1 ___| GLOBAL
| max-count : 6
(fact-iter 1 2 6)
E3 -->| product : 1 ^
| counter : 2 ____| GLOBAL
| max-count : 6
(fact-iter 2 3 6)
E4 -->| product : 2 ^
| counter : 3 _____| GLOBAL
| max-count : 6
(fact-iter 6 4 6)
E5 -->| product : 6 ^
| counter : 4 _____| GLOBAL
| max-count : 6
(fact-iter 24 5 6)
E6 -->| product : 24 ^
| counter : 5 _____| GLOBAL
| max-count : 6
(fact-iter 120 6 6)
E7 -->| product : 120 ^
| counter : 6 _____| GLOBAL
| max-count : 6
(fact-iter 720 7 6)
E8 -->| product : 720 ^
| counter : 7 _____| GLOBAL
| max-count : 6
720