How to read 'results' fromat in C++

[chenyanpei]

Hello everyone !
     I want to use the C++ program to read the results.txt of ImageJ. But after load the data seem so strange: Here is the C++ code :
    int main() {
       
        double Length, Width, LStrip, WStrip, NLStrip, NWStrip, NMeshLstrip, NMeshWstrip;
        double test[48];
        if(!experData){
                    cout << "Unable to open myfile";
                          exit(1); // terminate with error

                  }
        while (! experData.eof()){
                experData>>Length>>test[1]>>Width>>LStrip>>WStrip>> NLStrip>>NWStrip;
                 cout <<NWStrip<<"\n";

        }
 But the Output of NWStrips is 5.56182e-308. But I do not have this data in my files. How to read the" results" format file? Thank you

[dscho]

Hi Pei,

On Thu, 4 Aug 2011, Pei wrote:

>      I want to use the C++ program to read the results.txt of ImageJ. But after load the data seem so strange: Here is the C++ code :

You mean Results.txt with an upper-case 'R'. Even if you're on Windows, it
is a good habit to get into to pay attention to the case of the letters.

>     int main() {
>
> double Length, Width, LStrip, WStrip, NLStrip, NWStrip, NMeshLstrip, NMeshWstrip;
> double test[48];
> if(!experData){
>    cout << "Unable to open myfile";
>          exit(1); // terminate with error
>
>  }
> while (! experData.eof()){
> experData>>Length>>test[1]>>Width>>LStrip>>WStrip>> NLStrip>>NWStrip;
> cout <<NWStrip<<"\n";
>
> }
>  But the Output of NWStrips is 5.56182e-308. But I do not have this data in my files. How to read the" results" format file? Thank you

... [show rest of quote]

That number sounds awfully close to the smallest positive value you can
have with double precision floating points according to the IEEE standard:

        http://en.wikipedia.org/wiki/IEEE_754-2008#Basic_formats

Anyway, I gave it a try and this is what I came up with:

-- snipsnap --
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <vector>

std::istream& operator>>(std::istream& input_stream, std::vector<std::vector<double> >& table)
{
        std::string line;
        table.clear();

        while (std::getline(input_stream, line, '\n')) {
                std::istringstream parse_line(line);
                std::vector<double> row;
                std::string field;
                double value;

                while (std::getline(parse_line, field, '\t')) {
                        std::istringstream parse_field(field);
                        parse_field >> value;
                        row.push_back(value);
                }
                if (row.size() > 0)
                        table.push_back(row);
        }

        return input_stream;
}

int main(int argc, char **argv)
{
        std::ifstream input_stream(argv[1]);
        std::vector<std::vector<double> > table;

        input_stream >> table;

        std::cout << table.size() << " rows" << std::endl;

        for (int row = 0; row < table.size(); row++) {
                std::cout << "Row " << row << ": ";
                std::vector<double>& values = table[row];
                for (int column = 0; column < values.size(); column++)
                        std::cout << (column > 0 ? "; " : "") << values[column];
                std::cout << std::endl;
        }

        return 0;
}

[chenyanpei]

Thanks for your advice ！It works well in My eclipse. I will remember
the capitalization  "R ". You are good at stream of C++. Thank you
again!


2011/8/5 Johannes Schindelin <[hidden email]>

> Hi Pei,
>
> On Thu, 4 Aug 2011, Pei wrote:
>
> >      I want to use the C++ program to read the results.txt of ImageJ. But
> after load the data seem so strange: Here is the C++ code :
>
> You mean Results.txt with an upper-case 'R'. Even if you're on Windows, it
> is a good habit to get into to pay attention to the case of the letters.
>
> >     int main() {
> >
> >       double Length, Width, LStrip, WStrip, NLStrip, NWStrip,
> NMeshLstrip, NMeshWstrip;
> >       double test[48];
> >       if(!experData){
> >                   cout << "Unable to open myfile";
> >                         exit(1); // terminate with error
> >
> >                 }
> >       while (! experData.eof()){
> >               experData>>Length>>test[1]>>Width>>LStrip>>WStrip>>
> NLStrip>>NWStrip;
> >                cout <<NWStrip<<"\n";
> >
> >       }
> >  But the Output of NWStrips is 5.56182e-308. But I do not have this data
> in my files. How to read the" results" format file? Thank you
>
> That number sounds awfully close to the smallest positive value you can
> have with double precision floating points according to the IEEE standard:
>
>        http://en.wikipedia.org/wiki/IEEE_754-2008#Basic_formats
>
> Anyway, I gave it a try and this is what I came up with:
>
> -- snipsnap --
> #include <iostream>
> #include <fstream>
> #include <sstream>
> #include <string>
> #include <vector>
>
> std::istream& operator>>(std::istream& input_stream,
> std::vector<std::vector<double> >& table)
> {
>        std::string line;
>        table.clear();
>
>        while (std::getline(input_stream, line, '\n')) {
>                std::istringstream parse_line(line);
>                std::vector<double> row;
>                std::string field;
>                double value;
>
>                while (std::getline(parse_line, field, '\t')) {
>                        std::istringstream parse_field(field);
>                        parse_field >> value;
>                        row.push_back(value);
>                }
>                if (row.size() > 0)
>                        table.push_back(row);
>        }
>
>        return input_stream;
> }
>
> int main(int argc, char **argv)
> {
>        std::ifstream input_stream(argv[1]);
>        std::vector<std::vector<double> > table;
>
>        input_stream >> table;
>
>        std::cout << table.size() << " rows" << std::endl;
>
>        for (int row = 0; row < table.size(); row++) {
>                std::cout << "Row " << row << ": ";
>                std::vector<double>& values = table[row];
>                for (int column = 0; column < values.size(); column++)
>                        std::cout << (column > 0 ? "; " : "") <<
> values[column];
>                std::cout << std::endl;
>        }
>
>        return 0;
> }
>

... [show rest of quote]

--
Chen Yanpei, phD
MssMat
Ecole Centrale Paris
Grande voie des vignes
92295 Châtenay Malabry
Paris, France