Implementation Problems w/ the Package Calendar

[cis.ohio-state.edu!zaphod.mps.ohio-state.edu!malgudi.oar.net!zeus.frankli n.edu!hart@ucbvax.Berkeley.EDU (Drew Hart)]

am aenior working for my BSCS and am trying to teach myself the language
Ada. I am having difficulty w/ the data types used in the Package
Calendar. I am using a the following syntax: 

  t : time := clock;
  d : duration;
  begin --main program 
     t := clock;
     -- main function
     d := (t-clock);
  end prog;

I am trying to find the growth rate of several algorithms using big O
notation. My problem lies in trying to display the value held in d ( the
duration variable ). I cannot find a package (text_io, basic_num_io,
etc..) that will allow me to display (put) the variable d. 

Can anyone tell me how (or what package to use) to display a variable
with the data type of duration. Please send me a message directly (I am
not very expirienced w/ using the Internet). I can be reached at 
hart@franklin.edu . 

Your help is greatly appriciated,

Drew R. Hart I