Converting bstr_t to double

Question

How to do the transform bstr_t to double in c++?

I was thinking to convert to *char, then *char to double?

Answer 1

If you have a char* or wchar_t* string, use the strtod / wcstod functions to read a double.

Eg using @Steve's suggestion:

_bstr_t x;
double q = wcstod(x, NULL); // implicit conversion!
double p = strtod(x, NULL); // same

Apparently _bstr_t has implicit conversion operators both to const char * and const wchar_t* , so you can use them directly in the float parsing functions.

Answer 2

You can cast to const char* (there is a converter for this that handles mapping from wide char to MBCS under the covers) and then convert to double as you wish - stringstream::operator>> for example

Answer 3

Call wcstod or _wcstod_l if you want to control locale.

bstr_t myBstr_t = L"1.234";

double d = wcstod(myBstr_t, NULL);