The #define directive defines a character sequence called a symbol.
The existence or nonexistence of a symbol can be determined by #if or #elif
The general form for #define:
#define symbol
#define DEBUGLOG
using System;
class MainClass
{
public static void Main()
{
#if DEBUGLOG
Console.WriteLine("In Main - Debug Enabled");
#else
Console.WriteLine("In Main - No Debug");
#endif
}
}