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strange behavior in workspace

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larrry

strange behavior in workspace

I'm messing about with Project Euler problems and have noticed some behavior that I don't understand. This one happens to be very self-contained so I though I'd as for assistance.

This code (which doesn't solve the problem, btw) is buggy, but I can't see the bug and I'm beginning to suspect something in the VM or the class libraries. When I execute it, two odd things happen:

First, in spite of the block test [sum < 100] whileTrue:[...] it continues to run when sum > 100 (or a million for that matter).

Second, the block in the line:

(sum isPrime) ifTrue: [ (seq size > bestSeq size) ifTrue: [ bestSeq := seq copy.]]

executes even when sum is not a prime number.

Any help is appreciated.

-------------------------------

"Create a list of primes smaller than a million"

primes := OrderedCollection new.

2 to: 999999 do: [ :n | n isPrime ifTrue: [ primes add: n]].

bestSeq := OrderedCollection new.

seq := OrderedCollection new.

sum := 0.

[sum < 100] whileTrue: [

primes do: [:prime |

seq add: prime.

sum := seq sum.

(sum isPrime) ifTrue: [ (seq size > bestSeq size) ifTrue: [ bestSeq := seq copy.]]

]

larrry

Re: strange behavior in workspace

Ok. figured it out. whileTrue: only evaluates at the end of each block so it didn't evaluate.

I guess ignorance is not bliss, after all.

On Sun, Jan 8, 2012 at 10:05 AM, Larry White <[hidden email]> wrote:

I'm messing about with Project Euler problems and have noticed some behavior that I don't understand. This one happens to be very self-contained so I though I'd as for assistance.

This code (which doesn't solve the problem, btw) is buggy, but I can't see the bug and I'm beginning to suspect something in the VM or the class libraries. When I execute it, two odd things happen:

First, in spite of the block test [sum < 100] whileTrue:[...] it continues to run when sum > 100 (or a million for that matter).

Second, the block in the line:
(sum isPrime) ifTrue: [ (seq size > bestSeq size) ifTrue: [ bestSeq := seq copy.]]
executes even when sum is not a prime number.

Any help is appreciated.
-------------------------------
"Create a list of primes smaller than a million"
primes := OrderedCollection new.
2 to: 999999 do: [ :n | n isPrime ifTrue: [ primes add: n]].

bestSeq := OrderedCollection new.
seq := OrderedCollection new.
sum := 0.
[sum < 100] whileTrue: [
primes do: [:prime |

seq add: prime.
sum := seq sum.
(sum isPrime) ifTrue: [ (seq size > bestSeq size) ifTrue: [ bestSeq := seq copy.]]

]
].