Question

i have a text file with data like the following:

name
weight 
groupcode

name
weight
groupcode

name
weight
groupcode

now i want write the data of all persons into a output file till the maximum weight of 10000 kg is reached.

currently i have this:

 void loadData(){
            ifstream readFile( "inFile.txt" );
            if( !readFile.is_open() )
        {
            cout << "Cannot open file" << endl;
        }
            else
            {
                    cout << "Open file" << endl;
            }

            char row[30]; // max length of a value
            while(readFile.getline (row, 50))
            {
                    cout << row << endl;
                    // how can i store the data into a list and also calculating the total weight?
            }
            readFile.close();
    }

i work with visual studio 2010 professional!

because i am a c++ beginner there could be is a better way! i am open for any idea’s and suggestions

thanks in advance!

Answer 1

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <limits>

struct entry
{
    entry()
        : weight()
    { }

    std::string name;
    int weight; // kg
    std::string group_code;
};

// content of data.txt
// (without leading space)
//
// John
// 80
// Wrestler
// 
// Joe
// 75
// Cowboy


int main()
{
    std::ifstream stream("data.txt");
    if (stream)
    {
        std::vector<entry> entries;

        const int limit_total_weight = 10000;   // kg
        int total_weight = 0;                   // kg

        entry current;
        while (std::getline(stream, current.name) &&
               stream >> current.weight &&
               stream.ignore(std::numeric_limits<std::streamsize>::max(), '\n') &&  // skip the rest of the line containing the weight
               std::getline(stream, current.group_code))
        {
            entries.push_back(current);

            total_weight += current.weight;
            if (total_weight > limit_total_weight)
            {
                break;
            }

            // ignore empty line
            stream.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
        }
    }
    else
    {
        std::cerr << "could not open the file" << std::endl;
    }
}

Edit: Since you wannt to write the entries to a file, just stream out the entries instead of storing them in the vector. And of course you could overload the operator >> and operator << for the entry type.