(C/C++) two-dimensional dynamic array

RubberEagle

I'm currently working on a little program, and i need to make a 2 dimensional char-array, where (at least) one dimension isn't hardcoded.
(i know how to make a one-dimensional dynamic array using malloc and calloc)

it is a file list, that is going to be submitted to another function, and the dynamic part is the number of files. I'd use a stupid simple trick like a 1d array of structs (that include a char array), but the other function only understands a 2d char array (no, reprogramming the second function is not an option (for now) [img]http://216.15.145.59/mainforums/wink.gif[/img] )

Can anyone help? Please?
Thanks
RubberEagle

PJH

Ack, it's been so long I coded C++ last time. I can't even remember what malloc and calloc functions did.

I'm not sure, but if I recall correctly the dynamic arrays were done using pointers pointing to the last block of the array in the memory, so you didn't have to allocate any certain amount of memory for the arrays before hand. Or was it that the pointer pointed to a place in memory where then was the information where the last block of the array is located? Like I said, it's been a long time. [img]http://216.15.145.59/mainforums/rolleyes.gif[/img] If you don't know how to use pointers check out [url="http://www.cplusplus.com/"]http://www.cplusplus.com/[/url] or some other C-language website.

Biggles IIRC knows C++ pretty well. You there Les Bigg? [img]http://216.15.145.59/mainforums/biggrin.gif[/img]

- PJH

PJH

Here you should find what you need: [url="http://www.cplusplus.com/cgi-bin/search.cgi?q=dynamic+arrays"]http://www.cplusplus.com/cgi-bin/search.cgi?q=dynamic+arrays[/url]

- PJH

PJH

Read this: [url="http://www.cplusplus.com/doc/tutorial/tut3-3.html"]http://www.cplusplus.com/doc/tutorial/tut3-3.html[/url]

- PJH

RubberEagle

dynamic arrays with malloc and calloc work that way, that you create a (NULL)pointer, and then, when you know how much memmory you need, you allocate it with malloc or calloc...
thanks for the link, let's see what it does.. [img]http://216.15.145.59/mainforums/smile.gif[/img]

RubberEagle

Thanks a lot, the page you linked to didn't solve it, but the next page did it (i hope, have to try it).. i totally forgot about "new" and it looks like it accepts variables as array dimensions [img]http://216.15.145.59/mainforums/smile.gif[/img]

PJH

Good luck with it. I'm glad if it helped. [img]http://216.15.145.59/mainforums/smile.gif[/img]

- PJH

Biggles

Yep, new and delete should do the trick. Make sure when you delete it to use the correct form of delete. For arrays, this is delete[].

If you want to go all the way, make it a class with accessor functions and stuff like that. That way, you can encapsulate all the allocation and deallocation stuff. If you want to go even further and promote code reuse, make it a templated class. [img]http://216.15.145.59/mainforums/smile.gif[/img]

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RubberEagle

yep, but making it a class would again require me to reprogram the second function... (it's a file-archive creator)