Question

How do I convert a string to a floating point number if I want both comma interpreted as decimal comma and point interpreted as decimal point?

The code parses text files that have been created by our customers. They sometimes use decimal points and sometimes decimal commas but never thousand separators.

Answer 1

Use std::replace to do the hard work:

#include <cstdlib>
#include <string>
#include <algorithm>

double toDouble(std::string s){
    std::replace(s.begin(), s.end(), ',', '.');
    return std::atof(s.c_str());
}

If you need to cope with thousands separators it’d be much more tricky.