import Miranda 2.066 from upstream

1 files changed, 19 insertions, 0 deletions

diff --git a/miralib/ex/hamming.m b/miralib/ex/hamming.m
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+||this is a problem described by Dijkstra in his book, A Discipline of
+||Programming, and attributed by him to Dr Hamming, of Bell Labs.
+||Print in ascending order all numbers of the form
+|| 2**a.3**b.5**c        a,b,c all >=0
+||the solution here is based on a method using communicating processes.
+||ham is the list of numbers, to see them, say
+||  ham
+||hit control-C (interrupt) when you have seen enough!
+
+ham = 1 : foldr1 merge [mult 2 ham, mult 3 ham, mult 5 ham]
+      where
+      mult n x = [n*a|a<-x]
+      merge (a:x) (b:y) = a : merge x y,     if a=b
+			= a : merge x (b:y), if a<b
+			= b : merge (a:x) y, if a>b
+
+||Note  that  there  is  a  function  called  `merge'  in  the  standard
+||environment,  but  unlike  the  one  defined  above it does not remove
+||duplicates from the lists being merged.