On Jul 13, 2011, at 1:08 PM, H Bakkum wrote: > "Develop the function check-range1?, which consumes a list of > temperature measurements (represented as numbers) and checks whether > all measurements are between 5*C and 95*C." > ... > Everything works as it should, except when testing the program against > an empty list...it returns true, naturally. However, logically I feel > that an empty list should produce false, as it doesn't contain any > temperatures between 5*C and 95*C.
The question wasn't "are there any temperatures between 5 and 95?", it was "are there NO temperatures OUTSIDE the range of 5 to 95?" Which is clearly true of the empty list: it has no temperatures at all, hence certainly none outside that range. This is one of my favorite problems. A closely related problem is "Develop the function multiply-all, which consumes a list of numbers and returns the result of multiplying them all together." As with check-range1, the interesting question is "what's the right answer to the empty case?". Stephen Bloch sbl...@adelphi.edu _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
