预处理指令

/*
  Example4_17.cs illustrates the use of the
  #undef, #elif, and #else preprocessor directives
*/

#define DEBUG
#undef DEBUG
#define PRODUCTION

class Example4_17
{

  public static void Main()
  {

    int total = 0;
    int counter = 0;

    myLabel:
    counter++;
    total += counter;
    System.Console.WriteLine("counter = " + counter);
    if (counter < 5)
    {
#if DEBUG
      System.Console.WriteLine("goto myLabel");
#elif PRODUCTION
      System.Console.WriteLine("counter < 5");
#else
      System.Console.WriteLine("goto myLabel, counter < 5");
#endif
      goto myLabel;
    }

    System.Console.WriteLine("total = " + total);

  }

}

转载于:https://www.cnblogs.com/djcsch2001/archive/2011/05/03/2035676.html