Qt/QML interview Questions

Q)what is Qt ?
   Qt is a cross-platform application framework that is widely used for developing application        software that can be run on various software and hardware platforms with little or no change in the code.

Q)what is Qt creator?
Qt Creator provides a cross-platform, complete integrated development environment (IDE) for application developers to create applications for multiple desktop, embedded, and mobile device platforms, such as Android and iOS. It is available for Linux, mac-OS and Windows operating systems.

Q)what is Qt widgets?
Widgets are the basic building blocks for graphical user interface (GUI) applications built with Qt. Each GUI component (e.g. buttons, labels, text editor) is a widget that is placed somewhere within a user interface window, or is displayed as an independent window. Each type of widge is provided by a subclass of QWidget, which is itself a subclass of QObject.
QWidget is not an abstract class. It can be used as a container for other widgets, and it can be subclassed with minimal effort to create new, custom widgets. QWidget is often used to create a window inside which other QWidgets are placed.
As with QObjects, QWidgets can be created with parent objects to indicate ownership, ensuring that objects are deleted when they are no longer used. With widgets, these parent-child relationships have an additional meaning: Each child widget is displayed within the screen area occupied by its parent widget. This means that when you delete a window widget, all the child widgets it contains are also deleted.
Q)what is Q_OBJECTS macro?
The Q_OBJECT macro must appear in the private section of a class definition that declares its own signals and slots or that uses other services provided by Qt's meta-object system.
Q)what is MOC(meta object compiler)?

   The Meta-Object Compiler, moc, is the program that handles Qt's C++ extensions.
   The moc tool reads a C++ header file. If it finds one or more class declarations that contain the  Q_OBJECT macro, it produces a C++ source file containing the meta-object code for those classes. Among other things, meta-object code is required for the signals and slots mechanism, the run-time type information, and the dynamic property system.

Q)which  class is the parent class of QlineEdit ?

  QWidget is the parent class to all widgets(push button,line Edit,label like that).

Q)What is qmake?
qmake is a utility that automates the generation of Makefiles.
Makefiles are used by the program make to build executable programs from source code; therefore qmake is a make-makefile tool, or makemake for short.

QMake does not call g++/gcc directly. Instead, qmake creates native make files on your current platform. Under linux it creates standard GNU make files, under windows it can generate visual studio make files, under Mac OS X it can generate XCode project files. You then invoke your native build system (either GNU make, or MS NMake, or xcodebuild or whatever), which will call your native compiler (g++/gcc or whatever).


For more questions i will update soon.......

2 comments:

  1. Hello There,


    Hot! That was HOT! Glued to the Embedded Developers World your proficiency and style!


    I am trying to load a few lines ( many strings separated by a space) from a text file and break them into string tokens and store it as structure fields. This functions should be performed by the load items(item); function.
    However there is an anomaly. When I print the structure fields to check if they have been loaded properly, it turns out they are not!. when I print structure fields outside the load items(item); function the fields do not seem to be stored properly in the array.


    Thank you very much and will look for more postings from you.


    Many Thanks,
    Rinda

    ReplyDelete
  2. Hiya,

    I’ve often thought about this Embedded Developers World. Nice to have it laid out so clearly. Great eye opener.

    For some time now I have had (what I think are) a few great ideas for my own OS. I asked some of my friends that do computer programming if they could help me, but they all said that it is too much work that I should just look at Linux. I took their advice and did some googling and found out I can take Linux and make my own OS from it.
    This is a time-consuming process and during this time, any data on the volumes is unreachable. The journaling provided by the ext3 file system means that this sort of file system check is no longer necessary after an unclean system shutdown.
    Anyways great write up, your efforts are much appreciated.

    Grazie,
    Kevin

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