不忘本~explicit和implicit修饰符

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implicit 关键字用于声明隐式的用户定义类型转换运算符。如果转换过程可以确保不会造成数据丢失，则可使用该关键字在用户定义类型和其他类型之间进行隐式转换。

 1     class Digit
 2 
 3     {
 4 
 5         public Digit(double d) { val = d; }
 6 
 7         public double val;
 8 
 9  
10 
11  
12 
13         // User-defined conversion from Digit to double
14 
15         public static implicit operator double(Digit d)
16 
17         {
18 
19             return d.val;
20 
21         }
22 
23         //  User-defined conversion from double to Digit
24 
25         public static implicit operator Digit(double d)
26 
27         {
28 
29             return new Digit(d);
30 
31         }
32 
33     }
34 
35     class Program
36 
37     {
38 
39         static void Main(string[] args)
40 
41         {
42 
43             Digit dig = new Digit(7);
44 
45             //This call invokes the implicit "double" operator
46 
47             double num = dig;
48 
49             //This call invokes the implicit "Digit" operator
50 
51             Digit dig2 = 12;
52 
53             Console.WriteLine("num = {0} dig2 = {1}", num, dig2.val);
54 
55             Console.ReadLine();
56 
57         }
58 
59     }