I start with a matrix which has 10 columns and just one row, and I would like to add a seccond row below that one if the elements in the first row satisfy a certain property, add a third if the elements of the seccond one satisty a certain propery and so on.
Of course, I don't want to lose the elements in any of the rows after inserting a new one.
How do I do this?
You could declare a new matrix with sufficient space for the new row, copy the first row, assign your second row, and then copy your 3rd+ rows over. If you're not already aware of memcpy, it's a good way to copy contiguous sections of memory. (I'm assuming of course you're using arrays to implement the matrix).
Have you thought about making a large number of rows in your array. Then just adding data to it, as before. Your output (print or to file), would still show only the rows that are filled:
You may want to keep an int variable with the number of rows that are filled.Code:if(strlen(name)) { //print this row //this is a filled row } //or for(i=0;i<FilledRowsVariable; i++) //print this row
It's not all that trivial to keep mallocing or reallocating memory. Just free'ing all the memory you've requested, is a chore.
Last edited by Adak; 08-28-2010 at 10:30 AM.
I'm sorry but I can't build a matrix with a large enough number of rows, because the rows should grow dynamically
Switch to APL (A Programming Language).
Dyalog.com
Gustavo.
If you want to be happy one hour: take a nap
if you want to be happy one day: go fishing
If you want to be happy a year: inherit a fortune
if you want to be happy for a life time: HELP SOMEBODY
chinisse say.
Hey Gustaff, how come you wound up working in APL instead of the more common Python or Ruby?
What's do you like about APL? Any strong points you've seen?
Budala, did you check out the realloc link that Bayint posted, yet? Any problems so far?
