From 4e987026148fe65c323afbc93cd560c07bf06b3f Mon Sep 17 00:00:00 2001 From: Yale AI Dept Date: Wed, 14 Jul 1993 13:08:00 -0500 Subject: Import to github. --- progs/demo/pfac.hs | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) create mode 100644 progs/demo/pfac.hs (limited to 'progs/demo/pfac.hs') diff --git a/progs/demo/pfac.hs b/progs/demo/pfac.hs new file mode 100644 index 0000000..516fc85 --- /dev/null +++ b/progs/demo/pfac.hs @@ -0,0 +1,21 @@ + +-- This is a parallel varient of factorial + +module Main where + +fac :: Int -> Int +fac 0 = 1 +fac n = pfac 1 n + +pfac :: Int -> Int -> Int +pfac low high | low == high = low + | low + 1 == high = (low * high) + | otherwise = pfac low mid * pfac (mid + 1) high + where + mid = (high + low) `div` 2 + +main = appendChan stdout "Type in N: " abort $ + readChan stdin abort $ \ input -> + appendChan stdout (show (fac (read (head (lines input))))) abort done + + -- cgit v1.2.3