If an object (with a non-virtual destructor) is destroyed explicitly by applying the delete operator to a base-class pointer to the object, the base-class destructor function (matching the pointer type) is called on the object. There is a simple solution to this problem
A function is a method that returns a value other than void. Methods includes functions, subroutines, constructors, destructors, and properties.
Static member functions, member function templates and constructors cannot be virtual.
You cannot. Constructors are specific to the class in which they are declared. They cannot be inherited and so they cannot be virtual.
you have to initialize it into the "Constructor" which is a function without dataType and it's name is the same with the class nameEX:-class Exforsys{private:int a,b;public:Exforsys();...};Exforsys :: Exforsys(){a=0;b=0;}the EX from : http://www.exforsys.com/tutorials/c-plus-plus/class-constructors-and-destructors-in-c.htmlI recommend this link for You Under the title "Constructors and destructors" :http://www.cplusplus.com/doc/tutorial/classes/You can also See : http://www.win.tue.nl/~maubach/university/education/online-references/cpp/swartz/notescpp/oop-condestructors/constructors.html
Constructors allow class designers to initialise class attributes at the point of instantiation (whenever an object of the class is created). All classes must have at least one constructor other than the copy and move constructors otherwise it would be impossible to instantiate objects of the class. Copy and move constructors are not required but are generated automatically by the compiler unless the class designer explicitly marks them deleted from the class definition. The copy and move constructors allow new instances to be constructed from existing instances. The only difference between the two is that the move constructor transfers ownership of the member attributes, rather than merely copying them. In classes that contain pointers, the compiler-generated copy constructor only copies the pointer (a shallow copy) not what it points at (a deep copy). Thus class designers must provide a copy constructor in order to deep copy any unshared memory resources. Derived class constructors automatically invoke base class constructors, so classes are always constructed from the bottom up. Copy and move constructors automatically invoke their base class copy and move constructors, respectively, however all other constructors automatically invoke their base class default constructors, which may not be the most efficient method of construction. Thus class designers can invoke specific base class constructors through the constructor's own initialisation list (which is also used to initialise member attributes). Constructor bodies do not require any code except in those cases where initialisation is not possible with the initialisation list alone, however this is usually an indication of poor design choices rather than a limitation of the initialisation list. The initialisation list provides the most efficient mechanism for class initialisation. Every class must have one (and only one) destructor. If one is not provided by the class designer, the compiler generates one for you. However, unless the class contains a pointer to unshared memory, there is no need to define your own. Otherwise you must provide a destructor in order to release the memory. The destructor is the last chance to do so before an object of the class falls from scope. Classes that are intended to act as base classes must provide a virtual destructor (that is, the lowest base class must declared the destructor virtual). This ensures that if an object is destroyed polymorphically (via a pointer to one of its base classes), the most-derived destructor is always invoked first. Destruction of hierarchies is always top down. Note that destructors are not virtual by default for the simple reason that not all classes are intended to act as base classes. The containers provided by the Standard Template Library (STL) are a good example of this as none of the containers have virtual destructors -- so they cannot be used as base classes. Note that if any class method is declared virtual, the destructor must also be declared virtual. However, when inheriting from a base class with a virtual destructor, the class destructor is implicitly virtual (as are all virtual functions inherited from base classes) and does not need to be specified, although its good practice to explicitly include it anyway.
A function is a method that returns a value other than void. Methods includes functions, subroutines, constructors, destructors, and properties.
The order of constructors is determined by the sequence they are called in the code, starting with the base class constructor and moving to the derived class constructor. Destructors are called in the reverse order of constructors, starting with the derived class destructor and moving to the base class destructor.
Static member functions, member function templates and constructors cannot be virtual.
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.
1.Classes and Objects 2.Constructors and Destructors 3.Inheritance 4.Polymorphism 5.Dynamic Binding
You cannot. Constructors are specific to the class in which they are declared. They cannot be inherited and so they cannot be virtual.
Constructors & destructors are special member fns of a class. Constructor is a fn with the same name of the class and is used to initialize the object. ie automatic initialization is done by constructor. When an object is invoked then constuctor should be called. Similarly destructor is also a speial function is used to destroy the objects. Its name is also same as class name, but a tild(~) symbol should be used along with destruction function name. eg:~classname()
In C++ you have object constructors and object destructors. Both are called by the developer. In Java and C# you have constructors and finalizer methods, so Java and C# both have support for finalizer methods (also known simply as finalizer). So the finalizer methods are similar to the destructors of C++ with a very important twist, the finalizer method is called by the garbage collector when an object is freed and not by the programmer (like the destructors in C++). Both finalizers in Java, C# and destructors in C++ can be used to free resources such as sockets or file handles that the method is using. However, because the finalizer methods are called by the garbage collector the programmer has no control of when the finalizer method will be called. As such it is NOT A GOOD IDEA to use finalizer methods. One can write the methods of an object in such a way as to clean up after themselves.
you have to initialize it into the "Constructor" which is a function without dataType and it's name is the same with the class nameEX:-class Exforsys{private:int a,b;public:Exforsys();...};Exforsys :: Exforsys(){a=0;b=0;}the EX from : http://www.exforsys.com/tutorials/c-plus-plus/class-constructors-and-destructors-in-c.htmlI recommend this link for You Under the title "Constructors and destructors" :http://www.cplusplus.com/doc/tutorial/classes/You can also See : http://www.win.tue.nl/~maubach/university/education/online-references/cpp/swartz/notescpp/oop-condestructors/constructors.html
The Destructors - band - was created in 1977.
Constructors allow class designers to initialise class attributes at the point of instantiation (whenever an object of the class is created). All classes must have at least one constructor other than the copy and move constructors otherwise it would be impossible to instantiate objects of the class. Copy and move constructors are not required but are generated automatically by the compiler unless the class designer explicitly marks them deleted from the class definition. The copy and move constructors allow new instances to be constructed from existing instances. The only difference between the two is that the move constructor transfers ownership of the member attributes, rather than merely copying them. In classes that contain pointers, the compiler-generated copy constructor only copies the pointer (a shallow copy) not what it points at (a deep copy). Thus class designers must provide a copy constructor in order to deep copy any unshared memory resources. Derived class constructors automatically invoke base class constructors, so classes are always constructed from the bottom up. Copy and move constructors automatically invoke their base class copy and move constructors, respectively, however all other constructors automatically invoke their base class default constructors, which may not be the most efficient method of construction. Thus class designers can invoke specific base class constructors through the constructor's own initialisation list (which is also used to initialise member attributes). Constructor bodies do not require any code except in those cases where initialisation is not possible with the initialisation list alone, however this is usually an indication of poor design choices rather than a limitation of the initialisation list. The initialisation list provides the most efficient mechanism for class initialisation. Every class must have one (and only one) destructor. If one is not provided by the class designer, the compiler generates one for you. However, unless the class contains a pointer to unshared memory, there is no need to define your own. Otherwise you must provide a destructor in order to release the memory. The destructor is the last chance to do so before an object of the class falls from scope. Classes that are intended to act as base classes must provide a virtual destructor (that is, the lowest base class must declared the destructor virtual). This ensures that if an object is destroyed polymorphically (via a pointer to one of its base classes), the most-derived destructor is always invoked first. Destruction of hierarchies is always top down. Note that destructors are not virtual by default for the simple reason that not all classes are intended to act as base classes. The containers provided by the Standard Template Library (STL) are a good example of this as none of the containers have virtual destructors -- so they cannot be used as base classes. Note that if any class method is declared virtual, the destructor must also be declared virtual. However, when inheriting from a base class with a virtual destructor, the class destructor is implicitly virtual (as are all virtual functions inherited from base classes) and does not need to be specified, although its good practice to explicitly include it anyway.
it doesnt support destructors