code teaser

[Helevitia]

Interesting, good job Gurm and Rob.

Dave

[Chrono_Wanderer]

damn it, i jsut came home

pc++;

[Helevitia]

You know, I've been thinking about the third answer and it is actually very spectacular. I mean, think about it for a second. You have to take a condition that almost never uses the "+" sign to reach that condition.

Rob, how did you figure it out? I'm going to be impressed about this all day

[Taz-Matt]

In C and C++, and many other languages, 0 = False and everything else equals True. That's the reason why he found out.

Good job by the way!

[Rob(QG)]

In C it is quite common to see a construct such as:

if (a) { blah blah }

as a shorthand for:

if (a!=0) { blah blah }

Basically all expressions in C return a value, and if the return value is treated as either true or false (as in this case), then you have something to work with.

[Rob(QG)]

I suppose there is a logical way of getting the answer once you have answer 2:

for (i = 0; -i < n; i--)

loops when -i < n
stops when -i == n
therefore stops when 0==i+n

Wish I could say I had worked it out that scientifically

[Jammrock]

int i, n = 20;
for (i = 0; i < n; i--)
printf("-");

Ah, I see. It's a debug test.

LOL ... my mind is in a different plane of existence today. And it's not a very smart plane of existence.

Jammrock

[Helevitia]

My buddy at work wants to knwo if anyone else knows of any other code teasers? Alo, anybody know the link to some of the old brain teasers posted throughout the years?

Dave

[Ribbit]

FWIW, I figured you could also change the loop to:

for (i=40; i&lt;n; i--)

but I think that will actually print 21 dashes, not 20.

Rob, you're a genius.

[Chrono_Wanderer]

wow Rob

LOL@Ribbit!

[cjolley]

Originally posted by Ribbit
FWIW, I figured you could also change the loop to:

for (i=40; i&lt;n; i--)

but I think that will actually print 21 dashes, not 20.

Rob, you're a genius.

if i=40 and n=20 how does i&lt;n run even once?

Fun problem, sorry I missed it.
chuck

[Gurm]

Sorry Ribbit, Chuck's right. That wouldn't execute ever.

- Gurm

[Zao]

A friend of mine got Ribbit's solution too. It seemed right at first

[GuchiGuh]

n3rd4l3rt!!!!!!!

[Belwarrior]

another way might be even be the simplest

int i, n = 20;
for (i = 0; i < n; n--)
printf("-");

how about the above? my C is rusty but just changing n for i for the decrement should work.. no compiler with me so u have to check for me..

Edit: home at last to explain the logic
after you decrease n 20 times, u will have printed "-" 20 times and by now n=0 as the printf statement is executed before the n-- ,
and since i=0, i < n would cause the loop to end as zero is not equal to zero, this is a kind of reverse logic