Parsing CSV into Struct Array

Question

I am trying to parse CSV into Array of structures. Delimiter is ';'. If you look into the code it seems that I filled only first element of the array out of nine that is 9 lines are in my CSV right now. Remaining elements of the array are just 0. Anyone got some advice? Thanks

fileTO.open("imput.csv", ios_base :: app);
fileFROM.open("imput.csv", ios_base :: app);

//IntoCsvThruConsole();

// array of structures from csv

string line;

string sID, stype, scategory, samount, sdate;

int lines = CountExistingLines();

Properties * structure = new Properties[lines];
int counter = 0;
int position = 0;

while (getline(fileFROM, line))
    {
        sID = "";
        samount = "";

     for (int i = 0; i < line.size(); i++)
     {
      if (line[i] == ';')
      {
          position++;
          continue;
      }
      switch (position)
      {
          case 0 : sID = sID + line[i];
          break;

          case 1 : structure[counter].type = structure[counter].type + line[i];
          break;

          case 2 : structure[counter].category = structure[counter].category + line[i];
          break;

          case 3 : samount = samount + line[i];
          break;

          case 4 : structure[counter].date = structure[counter].date + line[i];
          break;
      }
     }
     structure[counter].ID = atoi(sID.c_str());
     structure[counter].amount = atoi(samount.c_str());

    cout << "ID zaznamu: " << structure[counter].ID << endl;
    cout << "Typ: " << structure[counter].type << endl;
    cout << "Kategorie: " << structure[counter].category << endl;
    cout << "Castka: " << structure[counter].amount << endl;
    cout << "Datum: " << structure[counter].date << endl;

    counter++;
    }

delete[] structure;

I have globally initialized struct correctly and also fstreams. Hope it is enough. Thanks

enter image description here

You should use vectors and not go char by char. Want me to post that solutions? — Jake Freeman
– Jake Freeman, Commented Dec 1, 2017 at 22:32
Semi-related : this for loop for (int i = 0; i < line.size(); i++) can be replaced almost entirely with std::stingstream stream(line); and a bunch of lines like std::getline(stream, sID, ';'); to read the tokens. — user4581301
– user4581301, Commented Dec 1, 2017 at 22:32
Very close example: stackoverflow.com/a/20303099/4581301 Actually, I'm going to propose this as a dupe. — user4581301
– user4581301, Commented Dec 1, 2017 at 22:34

Henri Menke · Accepted Answer · 2017-12-04 22:37:47Z

I recommend using Boost.Spirit for such parsing tasks.

#include <iostream>
#include <sstream>
#include <string>
#include <vector>

#include <boost/fusion/adapted.hpp>
#include <boost/spirit/home/x3.hpp>

struct Date
{
    int day;
    int month;
    int year;
};

std::ostream& operator<<(std::ostream& os, Date const &d)
{
    os << d.day << '/' << d.month << '/' << d.year;
    return os;
}

BOOST_FUSION_ADAPT_STRUCT(
    Date,
    day, month, year)

struct Properties
{
    int ID;
    std::string type;
    std::string category;
    int amount;
    Date date;
};

BOOST_FUSION_ADAPT_STRUCT(
    Properties,
    ID, type, category, amount, date)

std::vector<Properties> parse(std::string const &input)
{
    auto iter = input.begin();

    using namespace boost::spirit::x3;

    auto name = rule<class name, std::string>{}
        = lexeme[alpha >> *alpha];

    auto date = rule<class date, Date>{}
        = int_ > '/' > int_ > '/' > int_;

    std::vector<Properties> result;

    bool r = phrase_parse(iter, input.end(),
                          (int_ > ';' > name > ';' > name > ';' > int_ > ';' > date) % eol,
                          space - eol, result);

    if (!r)
    {
        std::string rest(iter, input.end());
        throw std::invalid_argument("Parsing failed at " + rest);
    }

    return result;
}


int main()
{
    // This could be a file instead with std::ifstream
    std::istringstream input;
    input.str(
        "1;TypeA;CategoryA;10;05/12/2017\n"
        "2;TypeB;CategoryA;21;04/12/2017\n"
        "3;TypeB;CategoryB;19;01/12/2017\n"
        "4;TypeA;CategoryA; 6;20/11/2017\n");

    std::vector<Properties> entry = parse(input.str());

    for (auto e :  entry)
    {
        std::cout << "Found the following entries:\n"
                  << "  ID: " << e.ID << "\n"
                  << "  Type: " << e.type << "\n"
                  << "  Category: " << e.category << "\n"
                  << "  Amount: " << e.amount << "\n"
                  << "  Date: " << e.date << "\n";
    }
}

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