Reading from text file

[jerkymotion]

I want to load the data from text file ..and i successfully did it by loading it in textbrowser....Now I want to load the specific characters into line edit whenever I encounter 0 in string of text file .....I succededd here but the program shows errror
Error message:::The application has requested the runtime to terminate in a unusual way
Please contact the application support team for more information
My Code::

void MainWindow::on_pushButton_clicked()
{
   QString filename = QFileDialog::getOpenFileName(this, tr("wew"),"",tr("allfiles(*.txt)"));
   QFile file(filename);
      if(file.open(QIODevice::ReadOnly | QIODevice::Text));
      {
      QTextStream in(&file);
         //QString mm;
 
      QString line;
      //char *ptr;
     // QByteArray ba;
         while (!in.atEnd())
      {
              line = in.readLine(0);//reads whole text file and loads it to Qstring line
             // ba=line.toLatin1();
 
 
//line.fromLatin1(ba,-1);
  ui->textBrowser->setText(line);
         }
 
         for(int i=0;i<=line.length();++i)
             {
 
             // ba=mm.toLatin1();
              //*ptr=ba.data();
             // if(line.at(i)==QChar('s'))
              //{
              //line.append("ssss");
              //}
            QChar ch=line.at(i).toAscii();
            int chvalue=ch.toAscii();
            if(chvalue==48)
            {
            ui->lineEdit->setText(ch);
            }
             }
 
        file.close();
 
    }
}

void MainWindow::on_pushButton_clicked()
{
   QString filename = QFileDialog::getOpenFileName(this, tr("wew"),"",tr("allfiles(*.txt)"));
   QFile file(filename);
      if(file.open(QIODevice::ReadOnly | QIODevice::Text));
      {
      QTextStream in(&file);
         //QString mm;

      QString line;
      //char *ptr;
     // QByteArray ba;
         while (!in.atEnd())
      {
              line = in.readLine(0);//reads whole text file and loads it to Qstring line
             // ba=line.toLatin1();


//line.fromLatin1(ba,-1);
  ui->textBrowser->setText(line);
         }

         for(int i=0;i<=line.length();++i)
             {

             // ba=mm.toLatin1();
              //*ptr=ba.data();
             // if(line.at(i)==QChar('s'))
              //{
              //line.append("ssss");
              //}
            QChar ch=line.at(i).toAscii();
            int chvalue=ch.toAscii();
            if(chvalue==48)
            {
            ui->lineEdit->setText(ch);
            }
             }

        file.close();

    }
}

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[schnitzel]

You might want to learn how to use Qt Creator's debugger.

[stampede]

void MainWindow::on_pushButton_clicked()
{
   QString filename = QFileDialog::getOpenFileName(this, tr("wew"),"",tr("allfiles(*.txt)"));
   QFile file(filename);
   if(file.open(QIODevice::ReadOnly | QIODevice::Text));
   {
      QTextStream in(&file);
      QString line;
      while (!in.atEnd())
      {
           line = in.readLine(0);//reads whole text file and loads it to Qstring line
           ui->textBrowser->setText(line);
      }
 
      for(int i=0;i<=line.length();++i)
      {
            QChar ch=line.at(i).toAscii();
            int chvalue=ch.toAscii();
            if(chvalue==48)
            {
            ui->lineEdit->setText(ch);
            }
      }
      file.close();
   }
}

void MainWindow::on_pushButton_clicked()
{
   QString filename = QFileDialog::getOpenFileName(this, tr("wew"),"",tr("allfiles(*.txt)"));
   QFile file(filename);
   if(file.open(QIODevice::ReadOnly | QIODevice::Text));
   {
      QTextStream in(&file);
      QString line;
      while (!in.atEnd())
      {
           line = in.readLine(0);//reads whole text file and loads it to Qstring line
           ui->textBrowser->setText(line);
      }
 
      for(int i=0;i<=line.length();++i)
      {
            QChar ch=line.at(i).toAscii();
            int chvalue=ch.toAscii();
            if(chvalue==48)
            {
            ui->lineEdit->setText(ch);
            }
      }
      file.close();
   }
}

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Looks better now, doesn't it ?
I don't know if you intend to do it this way, but you are testing for '0' only in last line of the file ( check the value of "line" after while loop ).
If you want to find a character in the string, you can use QString::indexOf method. Also there is no need to hardcode the ascii value for zero ( 48 is for '0' in your code, right ? ) and doing the QChar manipulations, line.indexOf("0") will work as expected.
Read QString documentation, it's full of useful informations.

edit:
about the crash - you should read documentation for QString::at().

[jerkymotion]

I have sucessfully read the whole text file(.txt file) in my text browser
and now I want to display all the 0's in text file to another textbowser_2
but my program only display one 0 in the textbrowser...
my text file content looks like this:
11110000
11110000
2222aaa
bbbb
and my code

void MainWindow::on_pushButton_clicked()
{
   QString filename = QFileDialog::getOpenFileName(this, tr("wew"),"",tr("allfiles(*.txt)"));
   QFile file(filename);
   QString line;
      if(file.open(QIODevice::ReadOnly | QIODevice::Text));
      {
      QTextStream in(&file);
 
         while (!in.atEnd())
      {
              line = in.readAll();//reads whole text file and loads it to Qstring line
              ui->textBrowser->setText(line);
         }
    }
      for(int i=0;i<line.length();i++)
          {
          QChar ch=line.at(i);
         int chvalue=ch.toAscii();//change to ascii value
         if(chvalue==48)//if 0 is encountered here
         {
 
         ui->textBrowser_2->setText(ch);//set the character value in another textbowser
         }
 
          }
     file.close();
}

void MainWindow::on_pushButton_clicked()
{
   QString filename = QFileDialog::getOpenFileName(this, tr("wew"),"",tr("allfiles(*.txt)"));
   QFile file(filename);
   QString line;
      if(file.open(QIODevice::ReadOnly | QIODevice::Text));
      {
      QTextStream in(&file);

         while (!in.atEnd())
      {
              line = in.readAll();//reads whole text file and loads it to Qstring line
              ui->textBrowser->setText(line);
         }
    }
      for(int i=0;i<line.length();i++)
          {
          QChar ch=line.at(i);
         int chvalue=ch.toAscii();//change to ascii value
         if(chvalue==48)//if 0 is encountered here
         {

         ui->textBrowser_2->setText(ch);//set the character value in another textbowser
         }

          }
     file.close();
}

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my output on textbrowser_2 is only one 0.....please help me

my ouput look like this

[stampede]

Read my previous post again - you are searching for zeros only in last line of the file, so put the "for" loop inside "while" loop.
Another thing is that if you call textBrowser2->setText(), it will clear previous content. Try with textBrowser_2->append().

[jerkymotion]

thank u stampede ..........It really worked!!!!!!!!!!