41 lines
1.1 KiB
C#
41 lines
1.1 KiB
C#
// sestoft@dina.kvl.dk * 2004-08
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using System;
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class MyTest {
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public static void Main(String[] args) {
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Foo<int?> fni1 = new Foo<int?>(null);
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Console.WriteLine(fni1.Fmt());
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Foo<int?> fni2 = new Foo<int?>(17);
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Console.WriteLine(fni2.Fmt());
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Foo<int> fi = new Foo<int>(7);
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Console.WriteLine(fi.Fmt());
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Foo<String> fs1 = new Foo<String>(null);
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Console.WriteLine(fs1.Fmt());
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Foo<String> fs2 = new Foo<String>("haha");
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Console.WriteLine(fs2.Fmt());
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}
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}
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class Foo<T> {
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T x;
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public Foo(T x) {
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this.x = x;
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}
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// This shows how to deal with tests for null in a generic setting
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// where null may mean both `null reference' and `null value of a
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// nullable type'. Namely, the test (x == null) will always be
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// false if the generic type parameter t is instantiated with a
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// nullable type. Reason: the null literal will be considered a
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// null reference and x will be boxed if a value type, and hence the
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// comparison will be false...
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public String Fmt() {
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if (x != null)
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return x.ToString();
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else
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return "null";
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}
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}
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