1.  
  2. double dub = -3.14;  
  3. Console.WriteLine(Math.Abs(dub));  
  4. Console.WriteLine(Math.Floor(dub));  
  5. Console.WriteLine(Math.Round(Math.Abs(dub)));  
  6.   
  7. // Output:  
  8. // 3.14  
  9. // -4  
  10. // 3  
  11.