final Specifier

 

You can use the final keyword to designate virtual functions that cannot be overridden in a derived class. You can also use it to designate classes that cannot be inherited.


function-declaration final;

class class-name final base-classes

final is context-sensitive and has special meaning only when it's used after a function declaration or class name; otherwise, it's not a reserved keyword.

When final is used in class declarations, base-classes is an optional part of the declaration.

Example

The following example uses the final keyword to specify that a virtual function cannot be overridden.

class BaseClass
{
    virtual void func() final;
};

class DerivedClass: public BaseClass
{
    virtual void func(); // compiler error: attempting to 
                         // override a final function
};

For information about how to specify that member functions can be overridden, see override Specifier.

The next example uses the final keyword to specify that a class cannot be inherited.

class BaseClass final 
{
};

class DerivedClass: public BaseClass // compiler error: BaseClass is 
                                     // marked as non-inheritable
{
};
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