1 class Program
 2     {
 3        //ref 和out类似c++指针，当然也不能拿来直接当指针用，是能引用一些参数，但是不能直接作为地址来控制参数（大概意思）
 4         static void Main(string[] args)
 5         {
 6             int a, b;
 7             OutTest(out a, out b);
 8             Console.WriteLine("a={0},b={1}",a,b);
 9             //output a = 1;b = 2;
10 
11             int c = 11, d = 22;
12             OutTest(out c, out d);
13             Console.WriteLine("a={0},b={1}", a, b);
14             //output c = 1;d = 2;
15 
16             int m = 11, n = 22;
17             //RefTest(ref m, ref n);
18             RefTest(ref m, ref n);
19             Console.WriteLine("m={0},n={1}", m, n);
20             //output m = 22;n = 11;
21 
22             Swap(m, n);
23             Console.WriteLine("m={0},n={1}", m, n);
24             //output m = 22;n = 11;
25         }
26 
27         static void OutTest(out int x, out int y)
28         {
29             //方法体外可以不用对传出参数赋值
30             //方法体内，必须对传出的参数赋值，否则报错，例如：x=y;
31             //适用于多个返回值的函数
32             x = 1;
33             y = 2;
34         }
35 
36         static void RefTest(ref int x, ref int y)
37         {
38 
39             //方法体外，必须对参数赋值，否则报错
40             //方法体内，ref对参数可以赋值也可以不赋值
41             //适合引用原值，并对原值修改
42             int temp = x;
43             x = y;
44             y = temp;
45         }
46 
47         static void Swap(int a, int b)
48         {
49             int temp = a;
50             a = b;
51             b = temp;
52         }
53     }