Mark Woodward
1/6/2009 10:40:00 AM
Hi all,
What is a SystemStackError?
Regarding code below:
If I run it with limit=10 and smallest_divisible(10), I get 2520 (right
answer), but it borks at 20. In the output I do get some numbers that
are divisible from 1 to 11, but no 12 (or higher). Could an output of 12
or higher be causing the SystemStackError? If so is there some way to
improve the code to eliminate the SystemStackError?
Funny how 23480 throws the error, but then further numbers are
processed. Then it stops completely at 24660!
--- code -------------------------------------------------------------
#!/usr/bin/env ruby
=begin
Project Euler - problem #5
2520 is the smallest number that can be divided by each of the numbers
from 1 to 10 without any remainder.
What is the smallest number that is evenly divisible by all of the
numbers from 1 to 20?
=end
def smallest_divisible(val)
limit = 20
puts val
(1..limit).each do |x|
print "x is #{x}, "
if val%x != 0
puts ""
smallest_divisible(val + limit)
end
end
puts "*** #{val} ***"
end
smallest_divisible(20)
--- part of the output ---------------------------------------
23280
x is 1, x is 2, x is 3, x is 4, x is 5, x is 6, x is 7,
23300
x is 1, x is 2, x is 3,
23320
x is 1, x is 2, x is 3,
23340
x is 1, x is 2, x is 3, x is 4, x is 5, x is 6, x is 7,
23360
x is 1, x is 2, x is 3,
23380
x is 1, x is 2, x is 3,
23400
x is 1, x is 2, x is 3, x is 4, x is 5, x is 6, x is 7,
23420
x is 1, x is 2, x is 3,
23440
x is 1, x is 2, x is 3,
23460
x is 1, x is 2, x is 3, x is 4, x is 5, x is 6, x is 7,
23480
x is euler/05/p5.rb:14:
in `smallest_divisible': stack level too deep (SystemStackError)
from euler/05/p5.rb:18:in `smallest_divisible'
from euler/05/p5.rb:14:in `each'
from euler/05/p5.rb:14:in `smallest_divisible'
from euler/05/p5.rb:18:in `smallest_divisible'
from euler/05/p5.rb:14:in `each'
from euler/05/p5.rb:14:in `smallest_divisible'
from euler/05/p5.rb:18:in `smallest_divisible'
from euler/05/p5.rb:14:in `each'
... 3685 levels...
from euler/05/p5.rb:18:in `smallest_divisible'
from euler/05/p5.rb:14:in `each'
from euler/05/p5.rb:14:in `smallest_divisible'
from euler/05/p5.rb:24
1, x is 2, x is 3,
23500
x is 1, x is 2, x is 3,
23520
x is 1, x is 2, x is 3, x is 4, x is 5, x is 6, x is 7, x is 8, x is 9,
23540
x is 1, x is 2, x is 3,
23560
x is 1, x is 2, x is 3,
23580
x is 1, x is 2, x is 3, x is 4, x is 5, x is 6, x is 7,
23600
x is 1, x is 2, x is 3,
... snipped ...
24580
x is 1, x is 2, x is 3,
24600
x is 1, x is 2, x is 3, x is 4, x is 5, x is 6, x is 7,
24620
x is 1, x is 2, x is 3,
24640
x is 1, x is 2, x is 3,
24660
cheers,
--
Mark