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Demonstrate #elif

The #else directive establishes an alternative if #if fails. #else marks both the end of the #if block and the beginning of the #else block. The #elif directive means "else if". The #elif directive establishes an if-else-if chain for multiple compilation options. #elif is followed by a symbol expression. There can be only one #endif associated with any #if. If the expression is true, that block of code is compiled, and no other #elif expressions are tested. The general form for #elif is #if symbol-expression        statement sequence      #elif symbol-expression        statement sequence      #elif symbol-expression       statement sequence      #elif symbol-expression       statement sequence      #elif symbol-expression      .     #endif #define AAA  #define RELEASE    using System;    class MainClass {    public static void Main() {            #if AAA        Console.WriteLine("Compiled for AAA version.");      #elif RELEASE        Console.WriteLine("Compiled for release.");      #else        Console.WriteLine("Compiled for internal testing.");      #endif        #if BBB && !RELEASE         Console.WriteLine("BBB version.");      #endif          Console.WriteLine("This is in all versions.");    }  } Compiled for AAA version. This is in all versions.