SICP lec1b: # Computing process

Computing process

kinds of expressions

number
symbols

---

lambda
definations
conditionals

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combinations

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condition

if

(define (+ x u)
(if (= x 0)
y
(+ (-1 x) (1 y))
)
)

Fibonacci

(define (fib n)    (if (< n 2)        n        (+  (fib (- n 1))            (fib (- n 1))        )    ))

---

tips: 1+ function means add args 1 and return

---

Hanoi Tower

(define (dohanoi n to from using)  (if (> n 0)      (begin        (dohanoi (- n 1) using from to)        (display "move ")        (display from)        (display " --> ")        (display to)        (newline)        (dohanoi (- n 1) to using from)        #t)      #f))(define (hanoi n)    (dohanoi n 3 1 2))