Copy 2d array from one to another

You can't do a memcpy on 2d array, actually it's array of pointers to other arrays. This can be useful in following context:

char **newArray = new char*[5];
for( int i=0; i<5; i++)
{
   newArray[i] = new char[5];
   memcpy( sourceArray[i], newArray[i], sizeof(char)*5 );
}

migotEx,

>>char **newArray = new char*[5];
What is "new" ? Is seems to be error.

Marcantilum,
>>memcpy (y, x, sizeof(x)); doesn't work because of value i copied is messing, with each position of array.

"new" is in C++,
you can use:

char **newArray = malloc(sizeof(char*) * 5);

Hi vannarith,

You can certainly use memcpy() to copy a two dimensional array!  MigoEX is correct in that there are some arrays where you'll not necessarily get the desired effect, but the example that you've shown is not a problem.


#define WIDTH  5
#define NEWWIDTH 80
#define HEIGHT 5

char x[HEIGHT][WIDTH] = {/* Some set of initializers  */};

char y[HEIGHT][NEWWIDTH];


  memset (y, 0, HEIGHT * NEWWIDTH);
  for (i = 0; i < HEIGHT; ++i)
    memcpy (y[i], x[i], WIDTH);



Kent

Hi migoEX,

I only posted because I thought that the previous posts were leading vannarith astray.  This is a C forum, not C++ so the new operator doesn't apply.  Even using malloc() instead of new is inaccurate because there are no pointers here.  The two arrays are contiguous memory blocks that hold character data.


Kent

So, again, for the example you gave with charx[5][5], to copy the data :)

memcpy (y, x, sizeof(x));

Did you accept randomly :)

Apparently, he did.  The accepted answer refers to 5 lines of C code, 4 of which are wrong.


Newbies.  sigh......

Yeah I think I won't answer anymore to vannarith questions :)

First he asked a question about "nano editor" saying <<nothing in Google>>
My first 2 lines of google results where the 2 links I gave as an answer - which matched perfectly the question...
I shouldn't have added "Try google" as vannarith felt offended and gave me a C grade...

I guessed our answers are beyond him, while they are simple basic C language.

My only concern is that EE serves sometimes as reference for some people looking for information.
The accepted answer and the other comment don't fit neither the question nor the C standards.
I think we should ask Sunny to get a look :)

Mercantilum,

>>Yeah I think I won't answer anymore to vannarith questions :)
-->Is that what you wanted?
-->I think you have offended me.

>>I shouldn't have added "Try google" as vannarith felt offended and gave me a C grade...
-->grade has been changed, since 3rd of June 1 day after this thread http://www.experts-exchange.com/Programming/Programming_Languages/C/Q_21007016.html,

Kdo,
>>>Apparently, he did.  The accepted answer refers to 5 lines of C code, 4 of which are wrong
-->I do relise that was c++. Ofcourse I did.!
--> While I was reading your answer close next migoEX. I did accept the wrong button. Your code is far understandable than migoEX.

>>Newbies
--> Remmber every one is newbie when they started.


Well Well, What a mess i've done. I've just realised that this thread is begen so tempting. I've just checked today. I want to make it clear.

Regards,

Thanks vannarith.

Mercantilum,
No worry. :)