More Factorials
Haskell, Iteration 4
Wikipedia lists a bunch of "Factorial-like products" ("products" in the mathematical sense, not the "factorial on a t-shirt" sense")
Your Turn
Pick two of these, an implement both of them two ways (patterns,
guards, ifs). So you'll have four new functions implementing two
new factorial-like products. Write tests that green bar. Do your
work in the existing files in
languages/haskell/factorial.
For your tests, you should have two assertions more than the number of base cases. (For example, the double factorial has two base cases, so you should have at least four assertions for it.) At least one of the assertions should be non-trivial. (Fortunately, wikipedia has the sequences right there.)