990324

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_3@409 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 9 insertions, 12 deletions

diff --git a/sample/sieve.rb b/sample/sieve.rb
index 5e9f792d81..359c185f20 100644
--- a/sample/sieve.rb
+++ b/sample/sieve.rb
@@ -1,17 +1,14 @@
 # sieve of Eratosthenes
-sieve = []
 max = Integer(ARGV.shift || 100)
+sieve = []
+for i in 2 .. max
+  sieve[i] = i
+end
 
-print "1"
-for i in 2 .. max 
-  begin
-    for d in sieve
-      fail if i % d == 0
-    end
-    print ", "
-    print i
-    sieve.push(i)
-  rescue
+for i in 2 .. Math.sqrt(max)
+  next unless sieve[i]
+  (i*i).step(max, i) do |j|
+    sieve[j] = nil
   end
 end
-print "\n"
+puts sieve.compact.join ", "