Setting up 2D array in C++ with wchar_t?

Asked Jan 26 '21 at 13:39

Active Jan 26 '21 at 13:53

Viewed 22 times

I'm confused on setting up a 2D unallocated pointer to an array without using a struct.

This compiles in a 1D array:

wchar_t *sServerArray = new wchar_t [128]();

But this does not compile:

wchar_t *sServerArray = new wchar_t [16][128]();

I'm missing something simple I think! Can someone help?

A struct would be something like this:

struct sServerArray 
    {
    TCHAR *sName;
    };
sServerArray *sGN = new sServerArray [128]();

Then allocate the memory:

for (INT i = 0; i<16; i++)
    {
    sGN[i].sName = (TCHAR*)calloc(16,sizeof(TCHAR));
    }

I can do auto, but do I also need to allocate memory for each of the 16 rows?

edited Jan 26 '21 at 13:53

asked Jan 26 '21 at 13:39

JeffR

C or C++ ? And how would you do this _with_ a struct? – Jabberwocky Jan 26 '21 at 13:40
Do like this: wchar_t *sServerArray = new wchar_t [16][128]; – sonulohani Jan 26 '21 at 13:44
1

@sonulohani You probably meant `wchar_t (*sServerArray)[128] = new wchar_t[16][128]{};` ? – Ted Lyngmo Jan 26 '21 at 13:50
Yes youre right – sonulohani Jan 26 '21 at 13:53
@sonulohani, are there 16 rows, with each row allocated 128 characters, or is it 128 rows, with 16 characters in each row in your example? – JeffR Jan 26 '21 at 14:06
@JeffR sonulohani's example isn't valid - but if the variable declaration had been ok you would have gotten 16 rows x 128 columns, `[16][128]`. It's usually easier to use a `std::vector data(16*128);` and to decorate that with accessors for calculating rows & columns. – Ted Lyngmo Jan 26 '21 at 14:31

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