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From: "John D'Errico" <woodchips@rochester.rr.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: sorting algorithm
Date: Wed, 3 Dec 2008 16:35:04 +0000 (UTC)
Organization: John D'Errico (1-3LEW5R)
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"Evren " <evrenbrs@gmail.com> wrote in message <gh6bfq$6b6$1@fred.mathworks.com>...
> "John D'Errico" <woodchips@rochester.rr.com> wrote in message <gh6b1b$s8t$1@fred.mathworks.com>...
> > "Evren " <evrenbrs@gmail.com> wrote in message <gh6alh$lvv$1@fred.mathworks.com>...
> > 
> > > > > I tried for hours and just can't seem to get it and its do tomorrow. If anyone can help, thank you very much. 
> > > > > 
> > > > > Here is what I got so far with some help, but it still doesn't work.
> > > > > 
> > > > > for i=1:(n-1)  % n is the length of the vector V 
> > > > >             if V(i)>V(i+1) 
> > > > >                     s = V(i); V(i) = V(i+1); V(i+1) = s; 
> > > > >             end 
> > > > > end
> > > > 
> > > > "develop your own sorting algorithm".  Why??
> > > > 
> > > > Sure you could research classical sorting methods and then implement one in Matlab, but what's the point?  Are you expected to dream up a wholly new scheme?
> > > 
> > > thats what i am expected to do.i must develop my sorting code.can you help me with this.what is the wrong with my code?
> > 
> > While this will work for two numbers, what happens when
> > you have 3 numbers? I.e., what if you use your code to
> > sort the numbers [3 2 1]? Try it. Are they in order? Why
> > did it fail? Look (carefully) at what it did.
> > 
> > John
> 
> i am trying to understand why it doesnt work but i cant figuger it out.what is the wrong?what can i do to work the code  for more than 5 numbers. i cant solve what to do..i even couldnt work the code yet...

Ok. Think about what would happen if you applied your
sorting scheme to the numbers a SECOND time. Would
a second pass through your scheme guarantee that three
numbers will always be sorted properly?

Why does a single loop such as your fails to give a sorted
vector? Apply it to the numbers [3 2 1]. The first test in
your loop will convert this set into [2 3 1]. Then the second
test yields [2 1 3]. These are clearly not sorted, yet you are
closer to that goal. 

Now make a second pass through. What happens? Think
about it. Then try again with the numbers [4 3 2 1]. Can
you sort them using your scheme? Will a second pass
succeed?

John