Question

I need to get some doubles from a string.

string data = getMyData();
char** next;
double start = strtod(data.c_str(), next);

if (&data == &(*next)) //check wether a double has been found - not working
{
    std::cerr << "Value can't be read.\nAborting.";
    return;
}

My idea is to check for memory address of data’s first char and next.
At the moment I’m learning C++ in self education so it would be nice to get the best solution and not just a working one.

Answer 1

It should be:

char* next;
double start = strtod(data.c_str(), &next);

if (data.c_str() == next)

Remember that next will point to the next comma if these are comma-separated, not the beginning of the next number.