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0220 Preprosessor directives

Preprosessor directives mark the code block for compiler. For example, #define DEBUG using System; class MyClass { int x; void aMethod() { # if DEBUG Console.WriteLine("Testing: x = {0}", x); # endif } } If DEBUG is defined C# will compile the statement. We can supply the flag with /define:Symbol through commandline. The following table lists all C# Preprosessor directives Preprocessor directive Action #define symbol Defines symbol #undef symbol Undefines symbol #if symbol [operator symbol2]... operators are ==, !=, &&, and || followed by #else, #elif, and #endif #else Executes code to subsequent #endif #elif symbol [operator symbol2] Combines #else branch and #if test #endif Ends conditional directives #warning text warning text for compiler output #error text error text for compiler output #line [ number ["file"] | hidden] number specifies the line in source code; file is the filename to appear in computer output; hidden instructs debuggers to skip over code from this point until the next #line directive #region name beginning of an outline #end region Ends an outline