std::vector<double> xs, ys;

std::ifstream infile("data.csv");

std::string line;

std::getline(infile, line); //ignore first line

while (std::getline(infile, line))
{
    std::istringstream iss(line);
    double x, y;
    char c;
    if (iss >> x) 
    { xs.push_back(x); }
    else break;
    iss >> c;   //eat the semicolon
    if(iss >> y)
    { ys.push_back(y); }
    else ys.push_back(Null);
}
infile.close();

Plot.AddSeries(xs.data(), ys.data(), xs.size());