Ex-3.3

(define (make-account balance secret-passwd)
  (define (withdraw amount)
    (if (>= balance amount)
        (begin (set! balance (- balance amount))
               balance)
        "Insufficient funds"))
  (define (deposit amount)
    (set! balance (+ balance amount))
    balance)
  (define (dispatch p m)
    (if (eq? p secret-passwd)
        (cond 
         ((eq? m 'withdraw) withdraw)
         ((eq? m 'deposit) deposit)
         (else (error "Unknown request -- MAKE-ACCOUNT"
                      m)))
        "Incorrect Password"))
  dispatch)