An array of LPWSTR pointers, not working right.

Question

Declare:

LPWSTR** lines= new LPWSTR*[totalLines];

then i set using:

lines[totalLines]=&totalText;
SetWindowText(totalChat,(LPWSTR)lines[totalLines]);
totalLines++;

Now I know totalText is right, cause if i SetWindowText using totalText it works fine. I need the text in totalLines too.

I'm also doing:

//accolating more memory.

  int orgSize=size;
  LPWSTR** tempArray;
  if (totalLines == size) { 
   size *= 2; 
   tempArray = new LPWSTR*[size]; 
   memcpy(tempArray, lines,sizeof(LPWSTR)*orgSize); 
   delete [] lines; 
    lines = tempArray; 
  }

to allocate more memory when needed.

My problem is that the lines is not getting the right data. It works for the first time around then it get corrupted. I thought at first i was overwriting but totalLines is increase. Hopefully this is enough information.

Answer 1

LPWSTR is already a pointer, so you're creating a 2D array of pointers - is that what you wanted? I think not, because this:

SetWindowText(totalChat,(LPWSTR)lines[totalLines]);

Casts LPWSTR* to LPWSTR. Isn't your compiler complaining?

Answer 2

These two statements:

LPWSTR** lines= new LPWSTR*[totalLines];
lines[totalLines]=&totalText;

invoke undefined behavior. The problem is that the maximum index of an array totalLines long is totalLines-1.

If you'd post what exactly you were trying to accomplish we might be able to help better. For example, it seems this problem could be much better solved with a std::vector<std::vector<wchar_t> > or std::vector<std::basic_string<wchar_t> > rather than an explicitly allocated array of LPWSTRs.

Answer 3

Thanks to Ben and Eli I have my answer. It should be LPWSTR* lines= new LPWSTR[size]; since LPWSTR is already a pointer. Thanks guys.