; string reverse

(define (stringrev inputString)
  (define len (string-length inputString))
  (define result "")
  (let loop((count len)) 
    (if(> count 0)
       (begin
       (set! result (string-append result (make-string 1 (string-ref inputString (- count 1)))))
       (loop (- count 1))
       ))
    result
    ) 
 )
input:
;(stringrev "karthi")
output:
"ihtrak"

_____________________________________
; fibonacci series

(define (fibonacci num)
  (define num1 0)
  (define num2 1)
  (define result(list))
  (let loop((count 0) (temp 0))
    (if(< count num)
       (begin
         (set! result (append result (list num1)))
         (set! temp num2)
         (set! num2 (+ num1 num2))
         (set! num1 temp)
         (loop (+ count 1) temp)
         )
       result
       )
    )
  )
input:
(fibonacci 5)
output:
(0 1 1 2 3)

___________________________
;struct

(define-struct std(roll name))
(define (pro clist)
 
  (std-roll (list-ref clist 0))
  (set-std-roll! (list-ref clist 0) 2)
  (std-roll (list-ref clist 0))
 
  )
 
(pro (list (make-std 11 "gg") (make-std 12 "tt")))
2


______________________________
(define (checkprime num)
  (if(< num 2)
     #f
     (begin
       (let loop((count 2) (end (round(sqrt num))))
         (if(<= count end)
            (begin
              (if(= (modulo num count) 0)
                 #f
                 (loop (+ count 1) end)
                           
                 )
              )
            #t
            )
         )
       )
     )
  )
;(checkprime 8)
;(checkprime 9)
;(checkprime 1)
;(checkprime 2)

(define (prime num)
  (define result(list))
  (let looping((count 2) (end num))
    (if(<= count num)
       (begin
         (if(checkprime count)
            (begin
            (set! result (append result (list count)))
            (looping (+ count 1) end)
            )
                        (looping (+ count 1) end)
                        )
         )
       result
       )
    )
  )
input:
(prime 50)
output:
(2 3 5 7 11 13 17 19 23 29 31 37 41 43 47)

Here I have listed some basic programs in scheme language. Ask me if you have any doubts :).

_____________________

;;Bubble sort

(define (bubble inputList)
  (define (swap inputList index1 index2)
    (let ((item1 (list-ref inputList index1)) (item2 (list-ref inputList index2)))
      (set-car! (list-tail inputList index1) item2)
      (set-car! (list-tail inputList index2) item1)
      )
      )
    (let loop1((count1 0) (len1 (- (length inputList) 1)))
      (if(< count1 len1)
           (begin
      (let loop2((count2 (+ count1 1)) (len2 (length inputList)))
                  
             (if(< count2 len2)
                 (begin
                  (if(> (list-ref inputList count1) (list-ref inputList count2))
                     (begin
                  (swap inputList count1 count2)
                  (loop2 (+ count2 1) len2)
                  )
                (loop2 (+ count2 1) len2)
                )
                  ) (loop1 (+ count1 1) len1)
                 )
                    
             
             )
        )inputList
      )
    ))
sample input:
(bubble (list 5 2 6 1 3))
output:
(1 2 3 5 6)