#lang racket

;zadanie 5
(define (odd? n)
  (cond [(zero? n) #f]
        [else (even? (- n 1))]))

;zadanie 6
(define (fibRek n)
  (cond
    ((= n 0) 0)
    ((= n 1) 1)
    (else (+ (fibRek (- n 1)) (fibRek(- n 2))))))

(define (fibIt n)
  (fib-iter 1 0 n))

(define (fib-iter a b count)
  (if (= count 0)
    b
    (fib-iter (+ a b) a (- count 1))))

;(fibRek 6)
;(fibIt 6)

;zadanie 7
(define (exp b e)
  (cond
    ((or (= b 1) (= e 0)) 1)
    ((= (modulo e 2) 0) (expt (exp b (/ e 2)) 2))
    (else (* b (exp b (- e 1))))))

;(exp 2 6)

;zadanie 8
(define (max-two a b c)
  (if (>= a  b)
      ;; then
      (if (>= b c)
          (cons a b)
          (cons a c))
      ;; else
   (if (>= a c)
      (cons b a)
      (cons b c))))
(define (sum-of-squares x y)
  (+ (* x x) (* y y)))
(define (sum-of-squares-of-maxima a b c)
  (sum-of-squares (car (max-two a b c)) (cdr (max-two a b c))))

;zadanie 9

(define (call f x)
  (f x))

;(call odd? 7)

;zadanie 10 - kolejność sprawdzania warunków

(define (new-if warunek alternatywa1 alternatywa2)
   (cond (warunek alternatywa1)
         (else    alternatywa2)))

;(new-if (> 1 2) 1 2)


;zadanie 12 - zasięg lokalny / globalny zmiennych
(define m 1)
(define (p m)
  (pp 5))
(define (pp x)
  (+ x m))

(define n 1)
(define (q n)
  (define (qq x)
         (+ x n))
  (qq 5))

;(p 11)
;(q 11)

;zadanie 1