Temperature

1) What do I need to store?
2) What types should be used?
3) What rules should I enforce?

data:
   degrees (double)	// must be > 0 Kelv (or equivalent)
   scale (char)		// can ONLY be k, K, f, F, c, C

functions:
   constructor(s)	// ensure the object gets initialized correctly
   destructor		// if any cleanup tasks

   Input		// keyboard input of a temperature
   Show			// print out a temperature
   Set			// mutator (set the temperature)
   GetScale		// accessors
   GetDegrees		// accessors
   Convert (to another scale)