SICP中square（开方）的实现（附C#实现）

#lang racket
(define (square x) (* x x))
(define (sqrt-iter guess x)
  (if (good-enough? guess x)
      guess
      (sqrt-iter (improve guess x)
                 x)))
(define (improve guess x)
  (average guess (/ x guess)))

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

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

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


(sqrt 9)

3.000000001396984
> 

 1 static void Main(string[] args)
 2         {
 3             double num1;
 4             int num2;
 5             Console.WriteLine("请输入要开方的值：");
 6             num1 = float.Parse(Console.ReadLine());
 7             Console.WriteLine("请输入精度");
 8             num2 = Int32.Parse(Console.ReadLine());
 9             num1 = square(num1,num2);
10             Console.WriteLine(num1);
11             Console.ReadLine();
12         }
13         static double square(double num,int num1)
14         {
15             double precision = Math.Pow(0.1, num1);//定义精度
16             double result = 1;//定义结果
17             while (Math.Abs( Math.Pow((num / result + result)/2, 2) - num) > precision)//
18             {
19 
20                 result = (num / result + result) / 2;
21             }
22 
23             return result;
24         }