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A virtual class is an instructional setting that is facilitated over the computer. The student logs in on the computer and receives lessons and delivers work electronically.
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Write abstract class in c plus plus?
An abstract class is any class definition that contains at least one pure-virtual function. class AbstractClass { public: virtual void DoSomething()=0; // Pure-virtual. };
What is true when a derivation inherits both a virtual and non-virtual instance of a base class?
Each derived class object has base objects only from the non virtual instance
What is the difference between abstarct class and virctulfunction in C sharp?
They are not comparable, but may have some relationship between them.An abstract class is a class, while a virtual function (or method) is a method. A method must exist within a class. Hence, a class has methods, and the methods may be defined as virtual functions.A virtual function must be defined in a class, but that class does not have to be an abstract class. However, the purpose of a virtual function in C# is to provide a default behavior/implementation, while allowing the derived class to override that default implementation, hence it makes no sense to define a virtual function in a sealed class (a leaf, that is, no class can extend from it, and it is not an abstract class)Example:public class Parent {public virtual string MostCommonPhrase() {return "You better listen to me...";}}public class Child : Parent {public override string MostCommonPhrase() {return "You never listen to me...";}}
How do virtual functions differ from pure virtual functions?
Virtual functions is a function that can be overridden in inheriting class with the same signature (function name, parameters number, parameters types and return type);Pure virtual function is function that does not have implementation and if class has pure virtual function is called abstract. It is not possible to instantiate that class. Some other class must inherit it and define the body for it (implement). In other words class only have function prototype/declaration(signature) and no definition(implementation).
What is the difference between virtual function and function overriding?
Virtual Functions and Pure Virtual Functions are relevant in the context of class inheritance.Unlike Virtual Functions, Pure Virtual Functions do not require a body. This implies that when a base class defining such a function is inherited, the derived class must implement that function. Furthermore, the base class becomes abstract; meaning you cannot create an instance of the base class even if a body is implemented for the function. You are expected to derive from abstract classes; only the derived classes that implement all the inherited Pure Virtual functions can be instantiated.Here are some examples of Virtual and Pure Virtual function signatures:- Virtual Function: E.g. virtual void myFunction();- Pure Virtual Function: E.g. virtual void myFunction() = 0;
What is the order of construction and destruction in c plus plus?
The least-derived base classes are always constructed first, in the order specified by the derived class inheritance list. The most-derived class (the one you are actually instantiating) is always constructed last. Destruction is basically the reverse of construction. However, base class destructors must be declared virtual to ensure that the most-derived class destructor is called first, regardless of which class destructor is actually invoked. That is, if you hold a pointer to a base class that has no virtual destructor, deleting that pointer will only destroy the base class, not the derived class, leaving the derived class in an invalid state (because it no longer has an underlying base class) and with no way to recover the memory it consumes. It is important to remember that if you declare any virtual methods within a class, you must also declare the destructor virtual. A class without a virtual destructor is not intended to be derived from. If it has virtual methods, but no virtual destructor, it is not well-formed and must not be used as a base class.
Is an abstract class virtual by default?
Unlike abstract class in C++, the abstract class in C# does not have any methods defined as virtual by default. The concept of virtual are not the same between C# and C++, either. Any virtual method must be defined explicitly in C#. Related to abstract methods - interestingly, an abstract class in C# does not have to have any abstract methods. However, the reverse, if a class need to have at least one abstract method, that class must be defined as abstract.
What is inheritance in visual c plus plus?
When you derive one class from another, the derived class inherits the sum of all the public and protected members exposed by the class it derives from. The underlying class is known as a base class and in the class hierarchy is an ancestor of the derived class. It is not necessary for the base class to know any of the details regarding its derivatives, as prudent use of virtual methods ensures the derived class acts correctly even when calling methods in the base class.
Do you use virtual functions in Java?
Every method in java that isn't a class (static) method is automatically "virtual." If you want to disable virtual overrides, make the method "final" in the base class.
Can you have inline virtual functions in a class?
No, inlining is done at compile time whereas virtual functions are resolved at run time(late binding). So, virtual functions can't be inlined. Both properties are orthogonal.Inlining is a mere suggestion the compiler may ignore it if it is declared with virtual function.
When do we make a virtual function pure?
We make a virtual function pure whenever we wish to make our class an abstract base class (an abstract data type). Unlike a virtual function, pure virtual functions must be overridden by a derived class or by one of its derivatives (the function remains pure virtual until it is overridden, at which point it becomes virtual). Derived classes that do not provide a complete implementation for all the pure virtual functions it inherits become abstract themselves. You cannot instantiate an abstract base class other than through derivation.
Why constructers can not be inherrited in c plus plus?
Every class of object must provide its own specific construction code. Since they are not really functions they cannot be overridden, thus they cannot be inherited. The same applies to the class destructor and the class self-assignment operator. Each class must handle these explicitly, within the class implementation. They cannot be implemented outside of the class, and therefore cannot be inherited. Although the virtual keyword can be applied to the destructor, it's not a function and therefore not a virtual function. The only reason for having a virtual destructor at all is when one or more of the class methods are virtual. Since classes with virtual methods are intended to act as generic interfaces for more specialised implementations, it's important that when destroying such a class that the most-derived (or most-specialised) class is destroyed first, working up the hierarchy to the base class which must always be destroyed last. This can only be achieved through virtual destruction. Failure to declare the base class destructor virtual could result in a base class being destroyed (such as when deleting a pointer to it), which would then result in an incomplete and therefore invalid derived class remaining in memory.
