How can I read and process data from a .txt file in c++ ?

[sakaflias]

Hi guys,

I'm a beginner in c++ and have relatively litle knowledge. So I would like to ask you if somebody can help me with my task. I hace to read data from a .txt file ( 34 columns and a lots of arrows) and then try to find the min, max and mean value from each column.I have tried to use fscaf but it doesn't seem to really work. Thanks in advance for your help

[kevinkjt2000]

I just helped out someone else that had a similar problem:
http://www.cplusplus.com/forum/beginner/153593/

To read data from a txt file you can use std::fstream
Examples can be found by clicking different function names
http://www.cplusplus.com/reference/fstream/fstream/

For example clicking (constructor) will show you how to create an std::fstream.
http://www.cplusplus.com/reference/fstream/fstream/fstream/

Clicking operator>> will show you how to read data from an fstream
http://www.cplusplus.com/reference/istream/istream/operator%3E%3E/

[DexterMorgan]

#include <string>
#include <fstream>

std::ifstream in("myfile.txt");

double input;

while (in >> input){
//do work
}

Sometimes, we have to work line by line in a file.
In such cases std::istringstream is quite helpful. You get a line, and treat that line as a stream.

#include <string>
#include <fstream>
#include <sstream>


std::ifstream in("myfile.txt");

if (in)
    {
      std::string line;
       while (std::getline(in, line)){
        std::istringstream split(line);
        double val;
        split >> val;
        std::string input;
        split >> input;
       }
     }