1.1确定分数与浮点数值之间的近似相等性。

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 
 7 namespace _03确定分数与浮点数值之间的近似相等性
 8 {
 9     class Program
10     {
11         static void Main(string[] args)
12         {
13             Console.WriteLine("输入第一个数的分子：");
14             var numerator = Console.ReadLine();
15             Console.WriteLine("输入第一个数的分母：");
16             var denominator = Console.ReadLine();
17             Console.WriteLine("请输入浮点型的比较值：");
18             var dblValue= Console.ReadLine();
19             Console.WriteLine("请输入精度：");
20             var epsilon = Console.ReadLine();
21             bool IsGoodApproximate= IsApproximatelyEqualTo(Convert.ToDouble(numerator), Convert.ToDouble(denominator), Convert.ToDouble(dblValue),Convert.ToDouble(epsilon));
22             if (IsGoodApproximate)
23             {
24                 Console.WriteLine("Good approximate");
25             }
26             else
27             {
28                 Console.WriteLine("Bad approximate");
29             }
30             Console.ReadKey();
31         }
32 
33         //使用System.Double.Epsilon值
34         public static bool IsApproximatelyEqualTo(double numerator, double denominator, double dblValue) 
35         {
36             return IsApproximatelyEqualTo(numerator, denominator, dblValue, double.Epsilon);
37         }
38 
39         private static bool IsApproximatelyEqualTo(double numerator, double denominator, double dblValue, double epsilon)
40         {
41             double difference = (numerator / denominator) - dblValue;
42             if (Math.Abs(difference)<epsilon)
43             {
44                 //这是一个很好的近似(足够近似）
45                 return true;
46             }
47             else
48             {
49                 //这是一个不好的近似（不够近似)
50                 return false;
51             }
52         }
53 
54     }
55 }