@phoopio/

# sicp

## No description

main.scm
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```
```(/ (+ 5 4 (- 2 (- 3 ( + 6 ( / 4 5 )))))
(* 3 (- 6 2)(- 2 7))
)

; 1.3 takes 3 numbers, return sum of squares of larger numbers

(define (square x) (* x x)
)

(define (bigger x y)(cond ((> x y ) x)
((> y x) y)
)
)

(define (squares a b c)(+
(square (bigger a b))
(square (bigger a c))
)
)

(squares 5 7 8)

; 1.7

(define guess 1)

(define (average x y)
(/ (+ x y) 2))

(define (abs x)
(if (< x 0)
(- x)
x))

(define (good-enough? guess x)
(< (abs (- guess (improve guess x)))
(* guess 0.001)))

(define (improve guess x)
(average guess (/ x guess)))

(define (sqrt-iter guess x)
(if (good-enough? guess x)
guess
(sqrt-iter (improve guess x)
x)))

(define (sqrt x)
(sqrt-iter 1.0 x))
(sqrt 2)

; 1.8
; (((x/ y^2) +2y)  /3)

(define (improve-cube guess x)
(/(+
(/ x (square guess))
(* guess 2)
)
3)
)

(define (cube-good? guess x)
(< (abs (- guess (improve-cube guess x)))
(* guess 0.001)))

(define (cube-iter guess x)
(if (cube-good? guess x)
guess
(cube-iter (improve-cube guess x)
x)))

(define (cubert x)
(cube-iter 1.0 x))
(cubert 5743895729340)

; 1. 11 compute f(n) recursively and iteratively

(define (g n)
(cond ((< n 3) n)
(else (+
(g (- n 1))
(* 2 (g (- n 2)))
(* 3 (g (- n 3)))
)
)
)
)

(g 5)

; iterative

(define (f n)
(define (iter a b c count)
(if (= count 0)
a
(iter b c (+ c (* 2 b) (* 3 a)) (- count 1)))
)
(iter 0 1 2 n)
)

(define (f n)
(if (< n 3) n)
(define (iter a b c count)
(- count 3)
(if (= count 0)
a
(
(define (temp a))
iter temp (* a 2) (* 2 c) (- count 1)
)
)
)
(iter 2 2 0)
)

(f 5)
```
BiwaScheme Interpreter version 0.6.4 Copyright (C) 2007-2014 Yutaka HARA and the BiwaScheme team