why do we subclass QWidget when we are creating a new class?

[majeed]

why do we subclass QWidget when we are creating a new class?

[JonB]

@majeed
You subclass QWidget --- or perhaps some more specific widget derived from QWidget --- if you are designing a new class which will be/behave like a widget. So that you get widget behaviour & functionality.

However, if your new class has nothing to do with widgets, you wouldn't subclass from QWidget....

[majeed]

sir why is it necessary to pass parent pointer to bass class constructor

[jsulm]

@majeed Please read http://doc.qt.io/qt-5/objecttrees.html

[majeed]

@jsulm why do we pass Qwidget pointer to the base class constructor?

[mrjj]

@majeed

Its the parent.
When parent is deleted it will delete all other widget that it is parent for.
Its auto clean up as the link
@jsulm shows. it explains it all.

[jsulm]

@majeed Did you read the link? If not why? It is explained there...