Assignment 5, Common Lisp

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; Curtis Sapp - Assignment 4 LISP - This program answers a bunch of homework questions and converts some java to LISP code

;2 is a function which returns the result of the addition of the two arguments.
; Run result would be
; 30
; 70
; 90

;public double add(double x, double y) {
;	return x + y;
;}

;3 is a function which prints all of the elements in a list recursivly

; Run result woud be
; 1
; 2
; 3
; 4
; 5

;public String myPrint(String list) {
;	if(list != null && list != "") {
;		System.out.println(list.charAt(0));
;		myPrint(list.subString(1, list.length));
;	}
;}

;4 An iterative function which calculates the factorial of an integer

(defun factorial1(n) 
    (let ((sum 1))
        (dotimes (i n)
            (setf sum (* sum(1+ i)))
        )
         
        sum
     )
)

;5 A recursive function which calculates the factorial of an integer

(defun factorial2(x) 
    (if (<= x 1)
        ;true
        1
        ;false
        (* (factorial2 (- x 1)) x)
    )
)

;6 a function that takes a list and returns the number of times the symbol 'a' occurs in it

(defun amount (n)

(cond
        ; if list is empty
        ((null n) 0)
        ; if first item in list is "a", recurssive call add +1 to stack
        ((equal 'a (car n)) (+ 1 (amount (cdr n))))
        ; else, 
        (t (amount (cdr n)))
    )
)

;7 a function which recursivly calculates a fibonacci number

(defun fib (n)
    (if (> n 0)
        ;true
        (if (= n 1)
            ;true
            1
            ;false
            (+ (fib (- n 1)) (fib (- n 2)))
         )
        ;false
        0
    )
)

;8 a function which returns the greater of two paramaters

(defun big(x y)
    (if (> x y)
        ;true
        x
        ;false
        y
    )
)

;9 a function which returns the sum of all integers less than equal to the paramter

(defun sum (n)
    (let ((total 0))
         (dotimes (i n)
             (setf total (+ total (+ i 1)))
         )
     total
     )
)

;10 describe what the code does

;(setq x '(a b)) ; returns list of parameters
;(setq y '(a b c)); returns list of parameters
;(print (car x)); returns a, symbol
;(print (car y)); returns a, symbol
;(print (cdr x)); returns (b), list
;(print (cdr y)); returns (b c), list
;(print (car (cdr x))); returns b, symbol
;(print (car (cdr y))); return b, symbol
;(print (cadr x)); returns b, sumbol
;(print (cadr y)); returns b, symbol
;(print (append x y)); returns (a b a b c), list

; test function
(defun test ()
	(print "CSE 240 Assignment 4. Curtis Sapp ")
	(print (factorial1 100))
	(print (factorial2 100))
	(print (amount '(b c (a) a)))
	(print (fib 7))
	(print (big 5 7))
	(print (sum 5))

)

(test)

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Absolute running time: 0.14 sec, cpu time: 0.06 sec, memory peak: 6 Mb, absolute service time: 0,15 sec