C++ file output duplicated

Question

So basically I'm supposed to make a database like application in c++. The problem I have is when I try to save/read from the .txt files I've created. Classes definitions and output functions:

file:table.h

#ifndef TABLE_H__
#define TABLE_H__

#include<iostream>
#include<vector>
#include<string>
#include<algorithm>
#include<functional>
#include<cstdio>

using namespace std;

class tableColumn
{
public:
    string colName;
    vector<string> tableCol;

    tableColumn() {};
    ~tableColumn() {};

    string getColName() { return colName; }
    void setColName(string);
    int getColSize() { return tableCol.size(); }

};


void tableColumn::setColName(string a)
{
    colName = a;
}

class tableMatrix
{
private:
    vector<tableColumn> table;
    string tableName;
public:
    tableMatrix() {};
    ~tableMatrix() {};

    string getTableName() { return tableName; }
    void setTableName(string);

    void saveToFile(string);
    void readFromFile(string);
};


void tableMatrix::saveToFile(string tableFileName)
{
    string aux;
    aux += tableFileName;
    aux += ".txt";

    ofstream out(aux.c_str());

    out << tableName << endl;
    out << table.at(1).getColSize() << endl;
    out << table.size() << endl;

    for (int i = 0; i < (int)table.size(); i++)
    {
        out << table.at(i).colName<<endl;
        for (int j = 0; j < (int)table.at(i).tableCol.size(); j++)
        {
            out << table.at(i).tableCol.at(j) << endl;
        }
    }
    out.close();
}

void tableMatrix::readFromFile(string tableFileName)
{
    string aux,element,space;
    int rows, cols;
    aux += tableFileName;
    aux += ".txt";

    ifstream in(aux.c_str());
    tableColumn auxc;

    getline(in, tableName);
    in >> rows;
    in >> cols;

    for (int i = 0; i < cols; i++)
    {
        in >> auxc.colName;
        for (int j = 0; j < rows; j++)
        {
            in >> element;
            auxc.tableCol.push_back(element);
        }
        table.push_back(auxc);
        auxc.~tableColumn();
    }
    in.close();
}

#endif

file:database.h

#ifndef DATABASE_H__
#define DATABASE_H__

#include<iostream>
#include<fstream>
#include<vector>
#include<algorithm>
#include<string>
#include"table.h"
#include<cstdio>

using namespace std;

class database
{
private:
    vector<tableMatrix> db;
public:
    database() {};
    ~database() {};

    void saveToFile();
    void readFromFile();
};


void database::saveToFile()
{

    ofstream out("tablenames.txt");

    for (int i = 0; i < (int)db.size(); i++)
    {
        out << db.at(i).getTableName() << endl;
    }
    out.close();

    vector<string> filenames;
    string aux;

    for (int i = 0; i < (int)db.size(); i++)
    {
        aux = db.at(i).getTableName();
        filenames.push_back(aux);
    }
    for (int i = 0; i < (int)db.size(); i++)
    {
        db.at(i).saveToFile(filenames.at(i));
    }
}

void database::readFromFile()
{
    vector<string>filenames;
    string aux;
    ifstream in("tablenames.txt");
    tableMatrix auxt;

    while (!in.eof())
    {
        in >> aux;
        filenames.push_back(aux);
    }
    for (int i = 0; i < (int)filenames.size(); i++)
    {
        auxt.readFromFile(filenames.at(i));
        db.push_back(auxt);
    }
    in.close();
}

#endif

main.cpp:

#include "stdafx.h"
#include<iostream>
#include<fstream>
#include"database.h"
#include<sstream>
#include<Windows.h>
#include<conio.h>
#include<vector>

using namespace std;

int main()
{
    database A;
    A.readFromFile();
    A.saveToFile();

    return 0;
}

file : tablenames.txt

aaa
asa2

file : aaa.txt

aaa
3
2
col1
1
2
3
col2
4
5
6

file : asa2.txt

asa2
3
2
col1
1
2
3
col2
4
5
67

Basically I want to create a txt file with all table names (tablenames.txt) and then a txt file for each table with its name and column data. However when I try to run it, it's duplicating my last entry in tablenames.txt and it messes up my table data by adding additional columns and/or rows.

For example, tablenames.txt : ramdomname1, ramdomname2 becomes: ramdomname1,ramdomname2,ramdomname2. Same deal with the other table files except that it does it on a larger scale (2 rows become 10 for example with duplicated/scrambled data).

Answer 1

Your output is correct, but your input is wrong. You are not supposed to use eof like this. The idiomatic loop goes like this:

while (in >> aux)
{
    filenames.push_back(aux);
}

Look at thousands of past Stack Overflow questions and answers about using C++ streams in loops.

Let's have a look again at your original code:

while (!in.eof())
{
    in >> aux;
    filenames.push_back(aux);
}

What happens here is that when EOF is encountered, no error has occurred yetthe EOF flag is only set when a read operation actually encountered EOF, so the loop condition still holds. The following call to operator>> does set the stream to an error stateEOF, but it's too late. The operation leaves aux unmodified, i.e. with the same value as before. That unmodified value is then pushed back to the vector again. Afterwards, the loop condition is checked again and finally fails (because the stream is in an error state).

In fact, for an even more robust approach, use the free-standing std::getline function and check every table name for correctness (e.g. not allowed characters, such as spaces or tabs):

std::string line;
while (std::getline(in, line))
{
    if (isCorrect(line))
    {
        filenames.push_back(line);
    }
    else
    {
        // error handling
    }
}

---

Edit: Some corrections on the explanation of original code.