blob: df5709472c92c72cd026e4f99614c241242976e0 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
|
// sestoft@dina.kvl.dk * 2004-08
using System;
class MyTest {
public static void Main(String[] args) {
Foo<int?> fni1 = new Foo<int?>(null);
Console.WriteLine(fni1.Fmt());
Foo<int?> fni2 = new Foo<int?>(17);
Console.WriteLine(fni2.Fmt());
Foo<int> fi = new Foo<int>(7);
Console.WriteLine(fi.Fmt());
Foo<String> fs1 = new Foo<String>(null);
Console.WriteLine(fs1.Fmt());
Foo<String> fs2 = new Foo<String>("haha");
Console.WriteLine(fs2.Fmt());
}
}
class Foo<T> {
T x;
public Foo(T x) {
this.x = x;
}
// This shows how to deal with tests for null in a generic setting
// where null may mean both `null reference' and `null value of a
// nullable type'. Namely, the test (x == null) will always be
// false if the generic type parameter t is instantiated with a
// nullable type. Reason: the null literal will be considered a
// null reference and x will be boxed if a value type, and hence the
// comparison will be false...
public String Fmt() {
if (x != null)
return x.ToString();
else
return "null";
}
}
|
