Question

char* timeNew = _com_util::ConvertBSTRToString(cpi->getTime());
if(timeFirst == true)
    {
    strcpy(timeOld,timeNew);
    timeFirst = false;
    }

how can I initiliase timeold if I dont know what the size of character array returned by cpi->getTime is?

Answer 1

Allocate memory for it based on length of timeNew:

delete[] timeOld;
timeOld = new char[strlen(timeNew) + 1];

or you could make timeOld a std::string and let it manage memory for you:

std::string timeOld;

timeOld = timeNew; // If timeNew is dynamically allocated you must still
                   // delete[] it when no longer required, as timeOld
                   // takes a copy of timeNew, not ownership of timeNew.

You can access the const char* using std::string::c_str() if really required.