From: Benjamin Thomas <benjamin.thomas81@...>
Date: 2009-03-12T05:45:42+09:00
Subject: Re: return doesn't always exit my method

Christopher Dicely wrote:

> Your intuition on where the problem is is correct. Note that when
> using recursion, each call to the function is a separate "layer", and
> calling return only jumps you out of the current layer. 

Thanks very much Christopher! I wasn't aware of this at all. I did run 
the code changes you provided and it helps!
I think I grasp the general concept but some aspects remain a mistery. 
Mainly I do not understand what the code is doing when it reverts to a 
previous "layer":

If the hash is new and fairly empty, the layers pop off in cascading 
style. No other bit of code seems to get executed.

this is the output I get when I type 'exit'

##########console output#############
creation!
iteration 0
1*8 = exit
will exit now
returning to rand_multi(12)
returning to rand_multi(11)
returning to rand_multi(10)
returning to rand_multi(9)
returning to rand_multi(8)
returning to rand_multi(7)
returning to rand_multi(6)
returning to rand_multi(5)
returning to rand_multi(4)
returning to rand_multi(3)
returning to rand_multi(2)
returning to rand_multi(1)
returning to rand_multi(0)
Bad answers:
7*6 => -1
######################################

But if the hash gets populated, the first part of the function gets 
executed from time to time and 'return' "sticks" to some layers.

This is the output I get then:

###############console output###################
6*1 = exit
will exit now
returning to rand_multi(30)
returning to rand_multi(29)
iteration 2
6*7 = exit
will exit now
returning to rand_multi(28)
iteration 2
6*7 = exit
will exit now
returning to rand_multi(27)
iteration 2
1*8 = exit
will exit now
returning to rand_multi(26)
returning to rand_multi(25)
returning to rand_multi(24)
returning to rand_multi(23)
iteration 2
1*3 =
#################################################
I would guess return brings me back to the exact same spot the recursive 
call got called. Is that correct? And in that case, wouldn't that mean 
that my function logic is fundamentally flawed because unpredictable?

Thanks very much Matt for your suggestion. Unfortunatly I cannot apply 
it here because I've barely touched procs and only have a vague idea of 
what throw and catch do. But it's definitly material for me to study so 
thanks!

Thank you also Udayanga. On first analysis, it's true that my 
"termination logic" was to input 'exit' at the prompt but I have also an 
infinite loop going on when I have answered all possible operations 
correctly with a score of 2 (the badly named variable 'iteration').
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