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The short answer is no, you cannot. The long answer is that constructors are not functions that can be called directly, and overriding a base class constructor would have no practical meaning since the derived class is itself responsible for calling its own base class constructors (whether implied by omission or explicitly via the derived class' initialisation list). Even so, the derived class isn't calling the base class constructor directly (that's why constructors have no return value; the actual call is made behind the scenes). The base class itself may be derived in which case its base class must be constructed before it can be constructed. This is the complete reverse of how a virtual function behaves, and is the reason that destructors can be virtual but constructors cannot. When a base class is destroyed, all its derivatives must be destroyed first, starting with the most-derived class of object. This can only be achieved through virtual destruction.
Wiki User
∙ 10y ago
Wiki User
∙ 9y agoNo.
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Constructor cannot be virtual but destructor can be virtual justify?
bcoz constructor cant be invoked
Can a constructor be declared as virtual?
A constructor cannot be virtual because at the time when the constructor is invoked the virtual table would not be available in the memory. Hence we cannot have a virtual constructor. ## Constructor called implicitly not explicitly so constructor is not virtual.
How can you create a virtual copy constructor?
You cannot. Constructors are specific to the class in which they are declared. They cannot be inherited and so they cannot be virtual.
What is a dynamic constructor?
dynamic constructor is a way to constructing an object based on the run type of some existing object. it basically uses standard virtual functions/polymorphism
1 Explain the concepts of constructor and destructor Do you have to declare a constructor every time you create a class?
You only need a constructor if the default constructor will not suffice. Often times, it is useful to have a constructor that takes common parameters so that you do not have to write additional code. For example, a Point class might have a constructor for Point(int x, int y), which would be a shortcut for assigning x and y independently. Other classes may not need any default values assigned, and for this, it is acceptable to just use the default constructor. Finally, some classes are virtual, static, or abstract, and so may not need a constructor because the constructor is unnecessary (static), or may be defined elsewhere (virtual, abstract).
What is the name of the special member function which is automatically called during creation of each class object?
The constructor. The constructor instantiates the object, and can optionally take parameters and has an optional initialization phase. It has no return type, and has the same name as the class itself. The constructor can be overloaded. It cannot be virtual or constant.
Are they any free virtual constructor or building programs you can use to design projects like pergolas or pavilions?
Try Google Sketchup.
How constructor is different from normal member function?
A constructor differs from a normal member function in three ways:A constructor never returns a result. The constructor's declaration reflects this by not even declaring the function as "void." The common design hypothesis is that a well-designed constructor cannot fail, other than maybe in an irrecoverable way (such as a fatal running out of memory).A constructor is never called explicitly except with the new operator.Constructors impose further restrictions. For example, they cannot be declared abstract or virtual, and may have visibility requirements. The common design practise is that at least the default constructor is declared public.
Default constructor in java?
If you don't type a constructor into your class code, a default constructor will be automatically generated by the compiler. The default constructor is ALWAYS a no-arg constructor. (Obviously the compiler has no clue what all arguments you might want for your class. So it takes the safe way out with a no argument constructor) A no-arg constructor is not necessarily the default (i.e., compiler-supplied) constructor, although the default constructor is always a no-arg constructor. The default constructor is the one the compiler provides! While the default constructor is always a no-arg constructor, you're free to put in your own no-arg constructor.
What is an empty constructor?
An empty constructor takes no arguments and calls the default constructor
What is a constructoris it mandatory to use constructor in a class?
You always should define default constructor for your class. You must also define a copy constructor for your class if there are any pointers in the class. While it is not mandatory, failure to provide a default constructor can result in bad behavior, and failure to provide a copy constructor when you have pointers in the class will result in bad behavior. For example, without a default constructor, the compiler will not fully initialize the attributes of the class. It will initialize the virtual function table, and call base class constructors, but that is all - the attributes could be random garbage. For another example, without a copy constructor, the compiler will generate one that simply makes a bit wise copy of the attributes. If these attributes contain pointers, then you have two pointers to the same object, not necessarily a good thing, especially if one of them get "deleted".
What is the difference between implicit and explicit call of constructor in c plus plus?
An implicit constructor call will always call the default constructor, whereas explicit constructor calls allow to chose the best constructor and passing of arguments into the constructor.
