QAbstractItemModel pure virtual function

[ozzy]

I learn Qt Mode/View from Qt example link text

QAbstractTableModel Inherits from QAbstractItemModel.

class MyModel : public QAbstractTableModel
{
    Q_OBJECT

public:
explicit MyModel(QObject *parent = 0);
int rowCount(const QModelIndex &parent) const;
int columnCount(const QModelIndex &parent) const;
QVariant data(const QModelIndex &index, int role) const;
}

I just implements 3 pure virtual function of QAbstractTableModel .

But there are 5 pure virtual function in QAbstractItemModel:

int rowCount(const QModelIndex &parent) const;
int columnCount(const QModelIndex &parent) const;
QVariant data(const QModelIndex &index, int role) const;
QModelIndex index (int row, int column, const QModelIndex & parent  ) const;
QModelIndex parent ( const QModelIndex & index ) const;

I read from book: You must implement all pure virtual funtions in base class so that you can create instance of subclass.

I don't implement all pure virtual funtions, why i can create MyModel instance ?

[Flotisable]

@ozzy
read the document

it says that QAbstractTableModel have provide default index() and parent()

[ozzy]

@Flotisable
You right,I'm so careless.