bittu.rkt

#lang racket

(struct student (roll name marks))

(define (get-input!)
  (read-line (current-input-port)))

(define (get-number!) (string->number (get-input!)))

(displayln "Enter the number of students")
(define num-students (get-number!))

(define class (foldl (λ (n c)
                       (displayln "Enter name")
                       (define name (get-input!))
                       (displayln "Enter marks")
                       (define marks (get-number!))
                       (append c (list (student n name marks))))
                     '()
                     (range num-students)))

(map (λ (c)
       (printf "~a~v~a\n" (student-roll c) (student-name c) (student-marks c)))
     class)
(define class-marks (map student-marks class))
(define average (/ (apply
      + (map student-marks class)) num-students))
(define greater-marks (filter (lambda (arg)
                              (> arg average))
                            class-marks))

(define less-marks (filter (lambda (arg)
                           (< arg average))
                         class-marks))%