;Zeming Chen
;A19b
;Final Exam Problems
	
#| write a procedure using call-with-values to 
	 split a list into two sets where each sets contains 
	 either the  elements with odd number index or the 
	 elements with even number index
|#

(define split
  (lambda (ls )
    (if (or (null? ls ) (null? (cdr ls )))
        (values ls ’())
        (call-with-values
          (lambda () (split (cddr ls )))
          (lambda (odd even )
            (values (cons (car ls ) odd )
              (cons (cadr ls ) even )))))))
       
 ;example	
 ;(split ’(a b c d e f )) ->
        ;(a c e)
				;(b d f )
				
#|
using the given code for a infinite loop and 
call/cc to write a counter that will print out the counts 
in every loop
|#

(define infinite-loop
	(lambda (procedure) 
		(letrec ((loop (lambda () 
			(procedure) 
				(loop)))) 
					(loop))))

(define count-to-n
	(lambda (n) 
		(let ((receiver (lambda (exit) 
			(let ((count 0)) 
				(infinite-loop 
					(lambda () 
						(if (= count n) 
								(exit count) 
								(begin (pretty-print "The count is: ")
                       (pretty-print count)
                       (set! count (+ count 1))))))))))
				(call/cc receiver))))
				
#|
(count-to-n 10)
"The count is: "
0
"The count is: "
1
"The count is: "
2
"The count is: "
3
"The count is: "
4
"The count is: "
5
"The count is: "
6
"The count is: "
7
"The count is: "
8
"The count is: "
9
10
|#