Constructors happen to initialize an object by default. Already a characteristic you should be familiar with from structures.

type T is tagged record
  F : Integer := Default_F;
  end record;

V1 : T;
V2 : T := (F => 0);

type T is new Ada.Finalization.Controlled with record
 F : Integer;
 end record;

procedure Initialize (Self : in out T) is
-- Initialuze = Constructor
-- Finalize
begin
 Put_Line ("Compute");
 Self.F := 0;
end Initialize;
V1 : T;
V2 : T := (f => 0);

Destructor

Liberate memory?