Importing text from a .txt file into a 2D array of strings

Question

I've been trying to import text from a .txt file into a 2D array of string, but it doesn't seem to be working. Each row in the .txt file has three values/elements separated that I need to copy.

This is the code:

// i am only allowed to use these libraries.
#include <iostream>
#include <fstream>
#include <string>
#include <stdlib.h>
using namespace std;

int main()
{
    const int rows = 38;
    const int columns = 3;

    string companies[rows][columns];

    // Inputting file contents
    ifstream file;
    
    file.open("companies.txt");

    while(!file.eof())
    {
        for(int i = 0; i < 38; i++)
        {
            for(int j = 0; j < 3; j++)
            {
                getline(file, companies[i][j], ',');
            }
        }
    }
    
    file.close();   
    
    cout << endl << endl;
    
    // displaying file contents using for loop

    for(int i = 0; i < 38; i++)
    {
        for(int j = 0; j < 3; j++)
        {
            cout << companies[i][j] << endl << endl;
        }
    }
    
    cout << endl << endl;

    return 0;               
}

This is the data that I want to import :

Symbol,Company Name,Stock Price
ATRL,Attock Refinery Ltd.,171.54
AVN,Avanceon Ltd. Consolidated,78.1
BAHL,Bank AL-Habib Ltd.,54.97
CHCC,Cherat Cement Company Ltd.,126.26

There are only three datas in each row seperaetd by commas i.e. a,b,c — Mr Moon Knight, Nov 25 '22 at 10:38
[Why is iostream::eof inside a loop condition (i.e. `while (!stream.eof())`) considered wrong?](https://stackoverflow.com/questions/5605125/why-is-iostreameof-inside-a-loop-condition-i-e-while-stream-eof-cons) — Remy Lebeau, Nov 25 '22 at 10:44

Remy Lebeau · Accepted Answer · 2022-11-25T11:16:25.863

One of the problems with your code is that you are only looking for , as a delimiter and not handling line breaks between the rows at all. Normally, I would suggest reading each row into a std::istringstream and then use std::getline(',') to parse each stream, but you say that you are not allowed to use <sstream>, so you will just have to parse each row manually using std::string::find() and std::string::substr() instead.

Also, using while(!file.eof()) is just plain wrong. Not just because it is the wrong way to use eof(), but also because your for loops are handling all of the data, so there is really nothing for the while loop to do.

Try something more like this instead:

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

int main()
{
    const int max_rows = 38;
    const int max_columns = 3;

    string companies[max_rows][max_columns];

    string line;
    string::size_type start, end;

    // Inputting file contents
    ifstream file("companies.txt");

    int rows = 0;
    while (rows < max_rows && getline(file, line))
    {
        start = 0;
        for(int j = 0; j < max_columns; ++j)
        {
            end = line.find(',', start);
            companies[rows][j] = line.substr(start, end-start);
            start = end + 1;
        }

        ++rows;
    }
    
    file.close();   
    
    cout << endl << endl;
    
    // displaying file contents using for loop

    for(int i = 0; i < rows; ++i)
    {
        for(int j = 0; j < max_columns; ++j)
        {
            cout << companies[i][j] << endl << endl;
        }
    }
    
    cout << endl << endl;

    return 0;               
}

Online Demo

Importing text from a .txt file into a 2D array of strings

1 Answers1