In my C++ project I am using string formatting as follows - 

```
sprintf(tag, "%g", "100.88");

```

If I run it in English locale it maps fine. I would like to make changes to it to work in different locales. Like in German locale tag should get assigned as 100,88.

How I can achieve this?

I am looking for something similar to 

```
system.convert.tostring(100.88 , 
                        system.globalization.culturalinfo.invariantculture)

```