Read data into double array with c++ - c++

Question

here is my problem. i have some two dimensional data with changing dimensionality, that i want to read into an 2d-array of doubles. Furthermore, there are at some points not number in the file but "NaN"s, that i want to be replaced by a zero. I made my code working so far, but i only managed to read integers. Maybe you could help me out to read it as doubles?
Here is what i got so far:
void READER(char filepath [], int target [129][128])
{
//---------------------------- header double & int
int rowA = 0;
int colA = 0;
std::string line;
std::string x;
std::cout << "reading file: " << filepath << "\n";
std::cout << std::endl;
std::ifstream fileIN;
fileIN.open(filepath);
if (!fileIN.good())
std::cerr << "READING ERROR IN FILE: " << filepath << std::endl;
while (fileIN.good())
{
while (getline(fileIN, line))
{
std::istringstream streamA(line);
colA = 0;
while (streamA >> x)
{
boost::algorithm::replace_all(x, "NaN", "0");
boost::algorithm::replace_all(x, ",", ""); //. rein
// std::cout << string_to_int(x) << std::endl;
target [rowA][colA] = string_to_int(x);
colA++;
}
rowA++;
if(rowA%5 ==0)
{
std::cout << "*";
}
}
}
std::cout << " done." <<std::endl;
}
this writes the files into 'target'. The function string to int looks the following:
int string_to_int (const std::string& s)
{
std::istringstream i(s);
int x;
if(!(i >> x))
return 0;
return x;
}
here you find some example data:

Answer 1

"exactly, thats what i thought about doing with the line boost::algorithm::replace_all(x, ",", ""); by replacing , by ."
Use following function to convert to any type, say double :-
template <typename T>
T StringToNumber ( const std::string &Text )
{
std::istringstream ss(Text);
T result;
return ss >> result ? result : 0;
}
Call using :
boost::algorithm::replace_all(x, ",", "."); // Change , to .
std::cout << StringToNumber<double>(x) << std::endl;
Or
you can simply use boost::lexical_cast
std::cout<<boost::lexical_cast<double>( x )<<std::endl;
Make sure you have a double 2D array