Override

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The override modifier:

  • is part of object-oriented programming;
  • allows a virtual and abstract method from a parent class to be overridden (replaced).

Example:

 Type
   TParentClass = class                           // The parent class is derived from the base class
   public
     function volume : double; virtual; abstract; // This method must be one from this class
                                                  // - derived class can be hidden or overridden
     function surface double; virtual; abstract;  // This method must be one from this class
                                                  // - derived class can be hidden or overridden
   end;

 Type
   TChildClass = class(ParentClass)               // The child class is derived from the parent class
   public
     function volume : double; override;          // the virtual method is overridden (replaced)
     function surface double; override;           // the virtual method is overridden (replaced)
   end;