How do you write a C plus plus program for destructor?

Answer 1

Class destructors define operations that will be performed whenever an object of the class falls from scope. This usually involves manually releasing any resources allocated to the object. However, by using resource handles or smart pointers, all resources will be released automatically, thus there is no need to define a destructor.

The only time we really need to define a destructor is when the class is intended to be used as a polymorphic base class (has one or more virtual methods) but does not inherit a virtual destructor, in which case we must define a virtual destructor. Classes that do define or inherit a virtual destructor cannot be used polymorphically. However, by using resource handles or smart pointers to manage resources, the destructor body can be left empty. The only reason for declaring the destructor at all is simply to declare it virtual because all methods are non-virtual by default -- unless they override a virtual method of the base class (in which case they can simply be declared as overrides).

The only time we need to define a non-empty destructor body is when implementing a resource handle or smart pointers, however the standard library already provides efficient implementations so, other than for educational purposes, there is no need to define our own resource handles.