Issue with deleting text in file - c++

Question

Explaining of my purpose:
my program have two section first reading two word from user(second word is meaning of first one) and save this words in two text file second section is showing or deleting words as desire of user.
What is my issue?:
my program works perfectly but after days will something like this happen:
when i try to delete two words from .txt files(i mean 1 word with meaning of it) first word will delete but second word(meaning) will not delete, it sounds like .txt file corrupted only thing that will fix every thing is delete that text file and create new one and thats very annoying that means lose all informations
note: first word and second word are in separate files. second words are still able to show.
what did i try?:
i try to check that is second word text file open or closed. that sounds like it will open or close in right time.
check that if text file is read-only. that wasnt.
i dont know what really happening here :( !!!!
here its my delete code am i missing something ?
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <fstream>
#include <QFile>
#include <QTextStream>
#include <QIODevice>
#include <QDebug>
#include <QMessageBox>
#include <QProcess>
#include <iostream>
#include <string>
#include <unistd.h>
using namespace std;
void newFunc();
void restartApp();
void makeFa();
int xy=-1;
ifstream sfile("en.txt");
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
newFunc();
ui->setupUi(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
void newFunc(){
QFile check("EnTemp.txt");
if(check.exists()){
}
else{
ofstream EnTemp("EnTemp.txt");
}
}
void restartApp()
{
qApp->quit();
QProcess::startDetached(qApp->arguments()[0], qApp->arguments());
}
void MainWindow::on_Enter_clicked()
{
if((ui->InEN->text().isEmpty()) || (ui->InFa->text().isEmpty())){
QMessageBox msg;
msg.setText("Fields are empty");
msg.exec();
}
else{
QString en,fa;
en=ui->InEN->text();
fa=ui->InFa->text();
// saving EN words
QFile dataE("en.txt");
dataE.open(QIODevice::WriteOnly | QIODevice::Append);
QTextStream streamE(&dataE);
streamE<<en<<"\r\n";
dataE.close();
// saving FA words
QFile DataF("fa.txt");
DataF.open(QIODevice::WriteOnly | QIODevice::Append);
QTextStream streamF(&DataF);
streamF.setCodec("UTF-8");
streamF<<fa<<"\r\n";
DataF.close();
ui->InEN->clear();
ui->InFa->clear();
}
}
void MainWindow::on_Next_clicked()
{
QFile EnTemp("EnTemp.txt");
EnTemp.open(QIODevice::WriteOnly);
QTextStream GetTemp(&EnTemp);
if(!sfile.eof()){
string get;
getline(sfile,get);
ui->ShowEn->setText(QString::fromStdString(get));
ui->ShowFa->clear();
xy++;
GetTemp<<xy;
EnTemp.close();
}
else{
restartApp();
}
}
void MainWindow::on_mean_clicked()
{
cout<<xy;
QFile openFa("fa.txt");
QString getFa;
openFa.open(QIODevice::ReadWrite);
QTextStream pointfa(&openFa);
pointfa.setCodec("UTF-8");
int forword=0;
while(forword<=xy){
getFa=pointfa.readLine();
forword++;
}
ui->ShowFa->setText(getFa);
openFa.close();
}
void MainWindow::on_delete_2_clicked()
{
makeFa();
ofstream tempE;
if(!ui->ShowEn->text().isEmpty() | !ui->ShowFa->text().isEmpty())
{
QMessageBox msg;
int ret;
msg.setText("Are you sure you want to delete this words?");
msg.setStandardButtons(QMessageBox::Yes | QMessageBox::No);
msg.setIcon(QMessageBox::Warning);
ret= msg.exec();
switch(ret){
case QMessageBox::Yes:
QString input;
input=ui->ShowEn->text();
string line;
ifstream DataE;
DataE.open("en.txt");
tempE.open("tempE.txt");
while(getline(DataE,line)){
if(line != input.toStdString()){
tempE<<line<<"\r\n";
}
}
QString inputF;
inputF= ui->ShowFa->text();
string lineF;
ifstream DataF;
ofstream tempF("tempF.txt");
DataF.open("fa.txt");
while(getline(DataF, lineF)){
if( lineF != inputF.toStdString()){
tempF<<lineF<<"\r\n";
}
}
DataE.close();
DataF.close();
tempE.close();
tempF.close();
sfile.close();
remove("en.txt");
remove("fa.txt");
rename("tempE.txt", "en.txt");
rename("tempF.txt", "fa.txt");
break;
}
}
else{
QMessageBox mass;
mass.setText("Fields are empty");
mass.exec();
}
restartApp();
}
void MainWindow::on_Restore_clicked()
{
xy= 0;
int reach=0;
string get;
QString s;
ifstream openTemp("EnTemp.txt");
openTemp>>xy;
while(reach<=xy){
getline(sfile,get);
reach++;
}
ui->ShowEn->setText(QString::fromStdString(get));
}
void makeFa(){
QFile tempF;
tempF.setFileName("tempF.txt");
tempF.open(QIODevice::ReadWrite | QIODevice::Append);
QTextStream stream(&tempF);
stream.setCodec("UTF-8");
tempF.close();
}
I'm on windows 8.1
i notice something new right now when i try to delete all information in second .txt file the size of file will be 3 bytes instead of 0 bytes

Answer 1

3 bytes for an otherwise empty file might match the UTF-8 BOM (not saying it is without knowing said bytes, but it is a strong hint). Your delete function might be fine (althought you should make the file filtering another function for clarity, and DRY), but would work only with ascii charset since you're relying on std::i/ofstream and std::string.
It might be (again, no certitude, just a wild guess) that you're creating a file with QFile, and that you put a "meaning" containing non-ascii characters and thus QFile automatically converts the file to an UTF-8 prefixed with BOM.
Would you mind updating your post with the file creation/update methods if you're uncertain of this lead?
[Edit] The other option would be that you're writing non ascii characters with ofstream which would probably lead to the "meaning" not being found, and thus the file being fully replicated.