3.8

A) (define (count l) (if (null? l)0 ( + 1 (count (cdr l)))))

B) (define (findmax l) (if (null? (cdr l)) (car l)

     (if (> (car l) (findmax (cdr l)))(car l)

     (findmax (cdr l)))))

C) (define (readnums) (let ((x (read))) (if (= x 0) '() (cons x (readnums)))))

D) (define (findmax l) (if (null? (cdr l)) (car l)

     (if (> (car l) (findmax (cdr l)))(car l)

     (findmax (cdr l)))))

     (define (findmin l) (if (null? (cdr l)) (car l)

     (if (< (car l) (findmin (cdr l))) (car l) (findmin (cdr l)))))

     (define (readnums) (let ((x (read)))

     (if (= x 0) '() (cons x (readnums)))))

    (define (minmax l) (define x l) (cons (findmin x) (list (findmax x))))

    /* Prints out the Min then Max into new list */

E) Quick Sort Scheme

F) Merge Sort Scheme

G) Haskell

pythriple n = [(x,y,z) | x <- [1..n], y <- [x..n], z <- [y..n], x^2 + y^2 == z^2]

Scheme SRFI-42

(define (pythriple n) (list-ec (:range x 1 n) (:range y x n) (:range z y n) (if (= (* z z) (+ (* x x) (* y y))) (list x y z))))

H) 8x 

(define square (lambda (x) (* x x))) 

(define twice (lambda (f) (lambda (x) (f (f x)))))

I)  (define ((inc_n n) x) 

        (cond [(> x 0) ((inc_n (+ n 1)) (- x 1))]

                  [else n]))