.NET Framework Standard Library Annotated Reference, Volume 1: Base Class Library and Extended Numerics Library

Example

using System;

namespace Samples
{
  public class BooleanSample
  {
    public static void Main()
    {
      Boolean b = true;
      if(b)
        Console.WriteLine("'b' is true");
      b = false;
      if(!b)
        Console.WriteLine("'b' is not true now");
    }
  }
}

The output is

'b' is true
'b' is not true now