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  1. // This is in the public domain
  2. using System;
  3. using System.Numerics;
  4. using static System.Console;
  5.  
  6. public static class Program
  7. {
  8. 	private static readonly string Rod = new string('-', 64);
  9.  
  10. 	public static void Main()
  11. 	{
  12. 		Test(Square(Math.PI), x => ToRational(x), n => (double)n);
  13. 		Test(Square((decimal)Math.PI), x => ToRational(x), n => (decimal)n);
  14. 	}
  15.  
  16. 	private static double Square(double x) => x * x;
  17.  
  18. 	private static decimal Square(decimal x) => x * x;
  19.  
  20. 	private static void Test<T>(T value, Func<T, ValueTuple<BigInteger, BigInteger>> toRational, Func<BigInteger, T> toT)
  21. 	{
  22. 		WriteLine(Rod);
  23. 		WriteLine($"value = {value}");
  24. 		var rational = toRational(value);
  25. 		BigInteger num = rational.Item1, den = rational.Item2;
  26. 		WriteLine($"rational = {num}/{den}");
  27. 		WriteLine($"rational - value = {(dynamic)toT(num) / toT(den) - value}");
  28. 	}
  29.  
  30. 	private static (BigInteger num, BigInteger den) ToRational(double value)
  31. 	{
  32. 		var gcd = GCD(value, 1);
  33. 		return ((BigInteger)(value / gcd), (BigInteger)(1 / gcd));
  34. 	}
  35.  
  36. 	private static (BigInteger num, BigInteger den) ToRational(decimal value)
  37. 	{
  38. 		var gcd = GCD(value, 1);
  39. 		return ((BigInteger)(value / gcd), (BigInteger)(1 / gcd));
  40. 	}
  41.  
  42. 	private static double GCD(double m, double n)
  43. 	{
  44. 		while (n != 0)
  45. 		{
  46. 			var rem = m % n;
  47. 			m = n;
  48. 			n = rem;
  49. 		}
  50. 		return m;
  51. 	}
  52.  
  53. 	private static decimal GCD(decimal m, decimal n)
  54. 	{
  55. 		while (n != 0)
  56. 		{
  57. 			var rem = m % n;
  58. 			m = n;
  59. 			n = rem;
  60. 		}
  61. 		return m;
  62. 	}
  63. }
Success #stdin #stdout 0.29s 33852KB
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stdin
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Standard input is empty
stdout
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----------------------------------------------------------------
value = 9.86960440108936
rational = 2778046668940015/281474976710656
rational - value = 0
----------------------------------------------------------------
value = 9.869604401089338270973592244
rational = 2467401100272334567743398061/250000000000000000000000000
rational - value = 0.000000000000000000000000000
https://ideone.com/tmPhPC
language:
C# (gmcs 5.20.1)
created:
2 years ago
visibility:
public

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