COS2614 Summary (Programming: Contemporary Concepts)

COS2614 Summary (Programming: Contemporary Concepts) c++ general summary: Creating class in QT: Right click on your project, say add new, then chose class. Then just type in class name and header and cpp file will automatically be created for you. Also, right click on a function and go refactor, then go add definition in .cpp file then it will create an auto implementation for you. General theory: Partial overriding: To implement an overridden function using partial overriding that means we call the overridden function in the overwriting function to calculate something. E.g. say calculateRental() was overridden double Video::calculateRental(int num) const{ double rental = Film::calculateRental(num); //calling the overridden function return (rental - (rental * discount / 100)) ; } Features of QMainWindow that allows for QAction objects: QMenu and QToolBar setCentralWidget(QWidget *wt) Note this function takes a QWidget object, but you can add view classes object inside as argument since the view class derived from QDialog or QMainWindow and those classes derive from QWidget. You can also put widgets like button as central widget since buttons derive from Viewclass which derive from QDialog which derives from QWidget. 3 visible features that can be added to QAction(sub menus) Text, icon, shortcut, tooltip Destructor when QMap and QList are data members Both fooLsit and fooMap point to Foo objects. The 1st statement deallocate the memory occupied by the objects. Now the 2nd statement tries to deallocate the Foo objects, but since they have already been deallocated a runtime error will occur. Sollution is to remove one of the statements. Implicit sharing application of Qt containers(lists) When a copy of a Qt container is made, the data values stored in the container are not copied unless a change is made to one or more elements of either container. Implicit sharing saves memory, and delays the process of copying containers until it is necessary Abstract class An abstract class is a class that is designed to be specifically used as a base class. An abstract class contains at least one pure virtual function which will get overridden by an inheriting class. Coutn function to check if there are repeated numbers in a list: foreach(int i, result){ if((i) > 1){ //here we use count function, count returns number on instances of argument in the list, result is the list message = "Input contains repetitions.";