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).
Code:
*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.
Code:
[>[-]>[-]<<[->+>+<<]>[-<,>>>[-]<[>+<-]<[>+<-]]>]
I haven't tested this, so see if it works :-)
