Question

My problem is the following. I try to convert a string into double. In this way:

string str = "1.1";
double d = atof(str.c_str());

But this don’t work, it simply return 1;

But if I try:

string str = "1,1";
double d = atof(str.c_str());

it return 1.1.

That is really weird. Seems it can only understand the number if I write a “,” but return as a “.”.

Any idea how could I solve this to convert “1.1” as well?

Answer 1

The function is locale aware, so it will parse the number according to your current locale settings.

Since atof is part of C library, you have to use C library to change the settings. Check out clocale.

Also have a look at C++ locale, which should be used if you use C++ features (string, istringstream) to parse the data. You can imbue the locale to the stream so that you don’t modify the global locale as in the case of C.