Follow the design recipe. A natural number is one of: -- 0 -- one more than n for some natural number n
Now create a template. Then fill the gaps. On May 28, 2011, at 2:50 PM, Krzysztof Adamczyk wrote: > I am having some difficulties with section 11.5 from htdp. I'm of course not > the first one encountering such problems: > > http://lists.racket-lang.org/users/archive/2008-November/028325.html > > but the above thread doesn't help in any way - Mr. Felleisen confirms that > one shouldn't assume that x is a natural number. But in his next post he says > that the function multiply from previous exercises should be used. Am I > missing or misunderstanding something? Is it possible to multiply x by x n > times with my multiply function when it needs both arguments to be natural > numbers? My first idea was to use a different function, say > multiply-by-inexact, which uses the + operator like multiply-by-pi, but it > still needs one natural argument to stop recursion. In which direction should > I go to solve this? My exponent function works for natural numbers, but I > don't want to miss anything important while going through this textbook. > > Krzysztof > _________________________________________________ > For list-related administrative tasks: > http://lists.racket-lang.org/listinfo/users
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