CODEWITHSUNDEEP
c++
Keith_Maxwell
Keith_Maxwell

Reputation: 94

Reading a file with getline function, but first column appears empty

I'm trying to read a file and write the data I read into a structure. With the getline function, i read the whole line, and then divide it in columns. Each term goes into an argument of the structure, and each line is a new instance of the structure. The problem is that my first column is empty.

The folowing code works partially, I read the whole file, all the other columns work perfectly but the first one is filled with nothing.

this is my structure and the data I put into it :

struct employe {
    int num_employe;
    string nom;
    string prenom;
    string date_naissance;
    string ville_resi;
    int code_postal;
};


employe saisir_1_employe(vector<string> row) {
    employe e;
    e.num_employe = stoi(row[0]);
    e.nom = row[1];
    e.prenom = row[2];
    e.date_naissance = row[3];
    e.ville_resi = row[4];
    e.code_postal = stoi(row[5]);
    return (e);
}

I extract the data from the file like this :

if (myfile.is_open()) {
        while (myfile >> temp) {

            row.clear();

            // read an entire row and
            // store it in a string variable 'line'
            getline(myfile, line, '\n');

            istringstream s(line);

            // read every column data of a row and
            // store it in a string variable, 'word'
            while (getline(s, word, '\t')) {

                // add all the column data
                // of a row to a vector
                row.push_back(word);
            }
            e = saisir_1_employe(row);
            afficher_1_employe(e);
        }

    }

my file I extract the data from looks like this : https://pastebin.com/Nfhu2tEp

When I display the second column (cout << row[1]) i get the names perfectly. But when I do cout << row[0] i get an empty column when it is supposed to be a string that I then convert to an int with e.num_employe = stoi(row[0]). It's there and has the right number of lines but just empty.

Upvotes: 1

Views: 858

Answers (2)

Gardener
Gardener

Reputation: 2660

Use getline() by itself to get each line There is no need to use this line:

while(myfile >> temp)

This is grabbing the first word and is never called again.

Instead, loop on each line, by calling getline() on the filestream directly:

while (getline(myfile, line, '\n'))

I like your use of stringstream to parse the words. I probably would have used a stringstream in the saisir function as well to do the parsing calls (e.g. instead of stoi()).

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

using namespace std;



struct employe {
    int num_employe;
    string nom;
    string prenom;
    string date_naissance;
    string ville_resi;
    int code_postal;
};

employe saisir_1_employe(vector<string> row )
{
  employe e;
  e.num_employe = stoi(row[0]);
  e.nom = row[1];
  e.prenom = row[2];
  e.date_naissance = row[3];
  e.ville_resi = row[4];
  e.code_postal = stoi(row[5]);
  return (e);
}

int main()
{
  fstream myfile{"myfile.txt"};
  std::string line;
  std::string word;
  std::vector<employe> employees;

  if (myfile.is_open()) {
    //    while (myfile >> temp) {
    //
    //      row.clear();

    // read an entire row and
    // store it in a string variable 'line'
    while (getline(myfile, line, '\n')) {
      std::vector<std::string> row;

      std::istringstream sline(line);

      // read every column data of a row and
      // store it in a string variable, 'word'

      while (getline(sline, word, '\t')) {

        // add all the column data
        // of a row to a vector
        row.push_back(word);
      }
      employe e;

      e = saisir_1_employe(row);
      employees.push_back(e);


//      afficher_1_employe(e);
    }

    int index = 1;

    // dump number and nom
    for(const auto& emp : employees) {
      std::cout << index++ << ". " << emp.num_employe
                << " " << emp.nom << std::endl;
    }

  }
}

Upvotes: 1

p-a-o-l-o
p-a-o-l-o

Reputation: 10047

I think you should loop like this

while(std::getline(myfile, line, '\n'))

instead of 

while (myfile >> temp)

which is cutting away the first word in every line ...

Upvotes: 2

Related Questions