Guided Practice 12.1

Consider the following set of class definitions and object definitions:

(define Class1%
  (class* object% ()
    (init-field a)
    (field [c (+ a 5)])

    (super-new)
    
    ;; Number -> Number
    (define/public (m1 x)
      (if (>= x 106) x
        (send this m2 (- x a))))
    
    ;; Number -> Number
    (define/public (m2 x) (+ x c))

    ))

(define Class2%
  (class* Class1% ()
    (inherit-field a c)
    (init-field b)

    (super-new [a (+ b 1)])

    ;; Number -> Number
    (define/override (m1 x) (- x c))
    
    ))

(define Class3%
  (class* Class1% ()
    (inherit-field a c)
    
    (super-new)

    ;; Number -> Number
    (define/override (m2 x) (send this m1 (+ x c)))

    ))

(define Class4%
  (class* Class2% ()
    (inherit-field a c)
    (super-new)
    (define/override (m2 x) (+ x c)) ))

(define obj1 (new Class1% [a 10]))
(define obj2 (new Class2% [b 20]))
(define obj3 (new Class3% [a 30]))
(define obj4 (new Class4% [b 40]))

Without running the program, determine the value of each pair of method calls below.

1. (send obj1 m1 100) and (send obj1 m2 100)

Answer:
a)	105 and 115
b)	105 and 130
c)	110 and 115

2. (send obj2 m1 100) and (send obj2 m2 100)

Answer:
a)	54 and 74
b)	74 and 126
c)	126 and 146

3. (send obj3 m1 100) and (send obj3 m2 100)

Answer
a)	110 and 126
b)	105 and 130
c)	110 and 130


4. (send obj4 m1 100) and (send obj4 m2 100)

Answer:
a)	105 and 146
b)	54 and 146
c)	115 and 146

[ANSWER]