1 public class MyClass2 {3     public static void UseParams(params int[] list)4     {5         for (int i = 0; i < list.Length; i++)6         {7             Console.Write(list[i] + " ");8         }9         Console.WriteLine();
10     }
11
12     public static void UseParams2(params object[] list)
13     {
14         for (int i = 0; i < list.Length; i++)
15         {
16             Console.Write(list[i] + " ");
17         }
18         Console.WriteLine();
19     }
20
21     static void Main()
22     {
23         // You can send a comma-separated list of arguments of the
24         // specified type.
25         UseParams(1, 2, 3, 4);
26         UseParams2(1, 'a', "test");
27
28         // A params parameter accepts zero or more arguments.
29         // The following calling statement displays only a blank line.
30         UseParams2();
31
32         // An array argument can be passed, as long as the array
33         // type matches the parameter type of the method being called.
34         int[] myIntArray = { 5, 6, 7, 8, 9 };
35         UseParams(myIntArray);
36
37         object[] myObjArray = { 2, 'b', "test", "again" };
38         UseParams2(myObjArray);
39
40         // The following call causes a compiler error because the object
41         // array cannot be converted into an integer array.
42         //UseParams(myObjArray);
43
44         // The following call does not cause an error, but the entire
45         // integer array becomes the first element of the params array.
46         UseParams2(myIntArray);
47     }
48 }
49 /*
50 Output:
51     1 2 3 4
52     1 a test
53
54     5 6 7 8 9
55     2 b test again
56     System.Int32[]
57 */

 1 class RefExample
 2 {
 3     static void Method(ref int i)
 4     {
 5         // Rest the mouse pointer over i to verify that it is an int.
 6         // The following statement would cause a compiler error if i
 7         // were boxed as an object.
 8         i = i + 44;
 9     }
10
11     static void Main()
12     {
13         int val = 1;
14         Method(ref val);
15         Console.WriteLine(val);
16
17         // Output: 45
18     }
19 }

 1 class OutReturnExample2 {3     static void Method(out int i, out string s1, out string s2)4     {5         i = 44;6         s1 = "I've been returned";7         s2 = null;8     }9     static void Main()
10     {
11         int value;
12         string str1, str2;
13         Method(out value, out str1, out str2);
14         // value is now 44
15         // str1 is now "I've been returned"
16         // str2 is (still) null;
17     }
18 }

1 class CS0663_Example
2 {
3     // Compiler error CS0663: "Cannot define overloaded
4     // methods that differ only on ref and out".
5     public void SampleMethod(out int i) { }
6     public void SampleMethod(ref int i) { }
7 }

1 class RefOverloadExample
2 {
3     public void SampleMethod(int i) { }
4     public void SampleMethod(ref int i) { }
5 }