Question

As a C++ noob, I can’t seem to get this right even though I know it should be simple :{ – I need to create an array of LPWSTR and then populate it with unique strings. The idea was to do something simple like this:

LPWSTR *wszArray = new LPWSTR[5];

for(int x = 0; x < 5; x++)
{
    swprintf(wszArray[x], "somestring_%d", x);
}

I know that I haven’t allocated memory for the LPWSTR, but after trying a few things I am not having much luck. Also I’m not sure if the array should be free’d later once i’m done with the strings.

Any advice would be great.

Answer 1

What you have right now is a single pointer to pointers to wide char. You’re then initializing that with the address of an array of 5 dynamically allocated pointers to wide char’s. That’s fine as far as it goes, but does not allocate any space for the strings themselves, only for pointers to 5 strings. You then need to allocate space for the strings themselves:

for (int i=0; i<5; i++) {
    array[i] = new char[13];
    swprintf(array[i], L"somestring_%d", i);
}

Yes, you should delete the space you allocated after you’re done using it. That would look something like:

for (int i=0; i<5; i++)
    delete [] array[i];
delete [] array;

OTOH, you probably shouldn’t do any of this, and instead use something like:

std::vector<std::wstring> array;

for (int i=0; i<5; i++) {
     std::wostringstream temp;
     temp << L"somestring_" << i;
     array.push_back(temp.str());
}

In this case, you can retrieve a “LPWSTR” using array[i].c_str(). You don’t have to allocate or free any of the memory explicitly at all though.