ASSERT failure in QVector<T>::operator[]: "index out of range" Error

[mena_mes]

Hi Everyone,

I want to count numer of lines in a file.

    QFile file("D:/test.txt");
    int line_count=0;
    file.open(QIODevice::ReadOnly); //| QIODevice::Text)
    QVector<QString> line;
    QTextStream in(&file);
    while( !in.atEnd())
    {
        line[line_count]=in.readLine();
        line_count++;
    }

and I get the error " ASSERT failure in QVector<T>::operator[]: "index out of range"

I know I have to add the size here QVector<QString> line (15000) ;

but I am not sure if the file contains more than 15000 for example.

Can anyone help me please :)

[mrjj]

Hi
Its the
line[line_count]

as line is
QVector<QString> line;
and it don't preallocate any entries beforehand.
(ah, you are aware of this. missed that)

so you want to do https://doc.qt.io/qt-5/qvector.html#append

line.append( readLine() );

[mrjj]

Hi
Its the
line[line_count]

as line is
QVector<QString> line;
and it don't preallocate any entries beforehand.
(ah, you are aware of this. missed that)

so you want to do https://doc.qt.io/qt-5/qvector.html#append

line.append( readLine() );