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authorchai <chaifix@163.com>2018-12-07 01:18:45 +0800
committerchai <chaifix@163.com>2018-12-07 01:18:45 +0800
commitafc5ebdeece428d4ef72f4f1f4b178a92d1b9cba (patch)
tree664aff4bdf9841346f044cb2a2f3cb4b55eba386 /src/3rdparty/lua-5.1.5/test/sieve.lua
parent1acc1ecf398bc43bc304a449643fddbb65d1e733 (diff)
+lua51
Diffstat (limited to 'src/3rdparty/lua-5.1.5/test/sieve.lua')
-rw-r--r--src/3rdparty/lua-5.1.5/test/sieve.lua29
1 files changed, 29 insertions, 0 deletions
diff --git a/src/3rdparty/lua-5.1.5/test/sieve.lua b/src/3rdparty/lua-5.1.5/test/sieve.lua
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+++ b/src/3rdparty/lua-5.1.5/test/sieve.lua
@@ -0,0 +1,29 @@
+-- the sieve of of Eratosthenes programmed with coroutines
+-- typical usage: lua -e N=1000 sieve.lua | column
+
+-- generate all the numbers from 2 to n
+function gen (n)
+ return coroutine.wrap(function ()
+ for i=2,n do coroutine.yield(i) end
+ end)
+end
+
+-- filter the numbers generated by `g', removing multiples of `p'
+function filter (p, g)
+ return coroutine.wrap(function ()
+ while 1 do
+ local n = g()
+ if n == nil then return end
+ if math.mod(n, p) ~= 0 then coroutine.yield(n) end
+ end
+ end)
+end
+
+N=N or 1000 -- from command line
+x = gen(N) -- generate primes up to N
+while 1 do
+ local n = x() -- pick a number until done
+ if n == nil then break end
+ print(n) -- must be a prime number
+ x = filter(n, x) -- now remove its multiples
+end