;; The first three lines of this file were inserted by DrScheme. They record metadata
;; about the language level of this file in a form that our tools can easily process.
#reader(lib "reader.ss" "plai" "lang")
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Some literals

1

"Hello"

'Williams

true

'(1 A B "Hello")

'((a b) (c d))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Calling a function

(list 1 2)

(+ 1 2)

(> 7 4)

(eq? 'x 'y)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; The IF expression

(if true 1 2)

(if false 1 2)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Factorial

;; defining a function:
(define (factorial n)
  (if (<= n 1)
      1
      (* (factorial (- n 1)))))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Find the largest element of a list

;; Defining a variable
(define minInt -10000)

; Takes a list and returns the largest value in the list
; or minInt if the list is empty (null)
(define (largest L)
  (if (null? L)
      minInt
      (max (first L)
           (largest (rest L)))))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Compute the absolute value of the argument
(define (absolute x)
  (if (< x 0)
      (- x)
      x))