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lazarus-tutorials/simple_examples/person_class.pas

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2021-10-04 14:33:07 -04:00
program person_class;
{$mode objfpc}{$H+}
uses sysutils, dateutils;
type
TPerson = class
FAwards: array of string;
FBirth, FDeath: TDate;
FName, FNationality, FRole: string;
constructor Create(aName, aNationality, aRole, aBirth, aDeath: string);
destructor Destroy; override;
function GetAwards(index: integer): string;
function GetLifespan: integer;
function GetNumberOfAwards: integer;
procedure DisplayInfo;
procedure SetAwards(index: integer; AValue: string);
property Awards[index: integer]: string read GetAwards write SetAwards;
property Birth: TDate read FBirth;
property Death: TDate read FDeath;
property Lifespan: integer read GetLifespan;
property Name: string read FName;
property NumberOfAwards: integer read GetNumberOfAwards;
property Role: string read FRole;
end;
function TPerson.GetAwards(index: integer): string;
begin
if Length(FAwards) > index
then Result := FAwards[index]
else Result := EmptyStr;
end;
function TPerson.GetNumberOfAwards: integer;
begin
Result := Length(FAwards);
end;
procedure TPerson.SetAwards(index: integer; AValue: string);
begin
SetLength(FAwards, index+1);
FAwards[index] := AValue;
end;
function TPerson.GetLifespan: integer;
begin
if FDeath = 0 then Result := YearsBetween(Now, FBirth)
else Result := YearsBetween(FDeath, FBirth);
end;
constructor TPerson.Create(aName, aNationality, aRole, aBirth, aDeath: string);
begin
inherited Create;
FName := aName;
FNationality := aNationality;
FRole := aRole;
FBirth := StrToDate(aBirth);
if (aDeath = EmptyStr) then FDeath := 0
else FDeath := StrToDate(aDeath);
end;
destructor TPerson.Destroy;
begin
SetLength(FAwards, 0);
inherited Destroy;
end;
procedure TPerson.DisplayInfo;
var n: integer;
begin
WriteLn('The ', FNationality, ' ', FRole, ' ', Name, ' was born on ', DateToStr(Birth));
case FDeath = 0 of
True: WriteLn(' is alive today and is ', Lifespan, ' years old');
False: WriteLn(' and died on ', DateToStr(Death), ' aged ', Lifespan, ' years');
end;
if NumberOfAwards > 0
then for n := Low(FAwards) to High(FAwards)
do WriteLn(' achieved in ', Awards[n]);
WriteLn;
end;
var person: TPerson;
begin
person := TPerson.Create(
'John Lennon',
'British',
'songwriter',
'09-10-1940',
'08-12-1980'
);
person.DisplayInfo;
person.Free;
person := TPerson.Create(
'Arvo Part',
'Estonian',
'composer',
'11-08-1935',
''
);
person.displayInfo;
person.Free;
person := TPerson.Create(
'Usain Bolt',
'Jamaican',
'sprinter',
'21-08-1986',
''
);
person.Awards[0] := 'Berlin 2009 100m world record of 9.58s';
person.Awards[1] := 'Berlin 2009 200m world record of 19.19s';
person.Awards[2] := 'London 2012 100m Olympic record of 9.69s';
person.Awards[3] := 'London 2012 200m Olympic record of 19.30s';
person.DisplayInfo;
person.Free;
{$IFDEF WINDOWS}
ReadLn;
{$ENDIF}
end.