Brainf#@k: an impossible program?

[cerin]

I have been playing around with the language Brainf#@k and have programmed a few novelty things with it all of them simple but still challenging. I have been trying at this one but I can't figure out how. I'm trying to have the program insert a blank piece of memory after every 8 characters of input. So far I have this:

>++++++++[>,[<]>-[>]<]>>

It will insert a blank piece of memory after the first 8 characters of input or skip a piece of memory however you want to look at it. My problem is getting this cycle to recur. I don't see how I could reset the 2nd memory block to 8 so it can happen again without actually copy and pasting the code many times. Can anyone help me out here?

[Rashakil Fol]

Why not just do the following?

+[,>,>,>,>,>,>,>,>>+]

[cerin]

Heh, thanks. A fairly simple solution. I guess I was thinking too deeply into it.

[Rashakil Fol]

If you want a more general solution, to say, increase the number from 8 up to anything less than 256, you should probably walk the counter with you (and walk a value N with you, too).

*set the pointer over the cell containing the number N*
*let's number this cell number 0*
*loop forever*
[
>[-]>[-]<<[->+>+<<] **copy cell 0 into 1 and 2

* We'll use cell 1 to count down to zero * cell 2 to keep track of N *
* and we'll march the cells rightwards *

> * put ptr on counting cell *
[   * While count hasn't reached zero *
-   * decrement counter *
<,> * read input char * ptr back on counter *
>  * ptr moves to cell that contains N *
>[-]<[>+<-] * move N one cell over * emptying current cell *
<
[>+<-] * move counter one cell over * emptying counter cell *
* ptr is now on counter cell *
]
* counter has now reached zero *
* move to the cell containing N *
>
* we've skipped the counter cell, which is now zero *
* now we're back on the cell containing N * just like at the top of the loop *
]

Here it is, more compressed.

[>[-]>[-]<<[->+>+<<]>[-<,>>>[-]<[>+<-]<[>+<-]]>]

I haven't tested this, so see if it works :-)

[cerin]

I tried to make a program that counts how many characters of input has been given. The issue I had with that is that if you just increment a certain piece of memory for each character received as input then there is the task of converting it to ascii values so you can display it.