Csharp/CSharp Tutorial/Preprocessing Directives/if
Demonstrate #else.
<source lang="csharp">#define AAA
- define BBB
using System;
class Test {
public static void Main() { #if AAA Console.WriteLine("Compiled for AAA version."); #else Console.WriteLine("Compiled for release."); #endif #if AAA && BBB Console.Error.WriteLine("Testing AAA and BBB version."); #else Console.Error.WriteLine("Not (AAA and BBB) version."); #endif Console.WriteLine("This is in all versions."); }
}</source>
Compiled for AAA version. Testing AAA and BBB version. This is in all versions.
Demonstrate #if, #endif, and #define.
- The #if and #endif directives enable conditional compilation.
- A symbol is true if it has been defined.
- A symbol is false if it has not been defined.
- If a symbol has been defined by a #define directive, the symbol true.
The general form of #if is
<source lang="csharp">#if symbol-expression
statement sequence #endif</source>