Interface

type

pPersonType = ^PersonType;

PersonType = record

sName: string[40];

Salary: double;

pNext: pPersonType;

end;

MyList1Class = Class(TObject)

protected

pHead, pTail: pPersonType;

public

constructor Create;

destructor Destroy;

function AloneItem(sName: string; Salary: double;

var pNew: pPersonType): boolean;

procedure AppendItem(sName: string; Salary: double);

procedure AppendFromFile(sFileName: string);

procedure ShowList;

end;

Implementation

constructor MyList1Class.Create;

begin

pHead := Nil;

pTail := Nil;

end;

destructor MyList1Class.Destroy;

begin

// Код будет написан позже!

end;

function MyList1Class.AloneItem(sName: string; Salary: double;

var pNew: pPersonType): boolean;

begin

New(pNew);

if pNew = Nil then Halt; // Нет места в памяти – прекращаем работу.

pNew^.sName := sName;

pNew^.Salary := Salary;

pNew^.pNext := Nil;

if pHead = Nil then

begin

pHead := pNew; pTail := pNew;

AloneItem := True;

end

else

AloneItem := False;

end;

procedure MyList1Class.AppendItem(sName: string; Salary: double);

var

pNew: pPersonType;

begin

if not AloneItem(sName, Salary, pNew) then

begin

pTail^.pNext := pNew;

pTail := pNew;

end;

end;

procedure MyList1Class.AppendFromFile(sFileName: string);

var

F: Text;

sName: string[40];

Salary: double;

begin

Assign(F, sFileName);

{$I-}

Reset(F);

{$I+}

if IOResult <> 0 then

begin

WriteLN('File ', sFileName, ' not found');

Halt;

end;

while not EOF(F) do

begin

Readln(F, sName);

Readln(F, Salary);

AppendItem(sName, Salary);

end;

end;

procedure MyList1Class.ShowList;

begin

pCurr := pHead;

Writeln('Name':40, ' ', 'Salary');

Writeln('----':40, ' ', '------');

while pCurr <> Nil do

begin

Writeln(pCurr^.sName:40, ' ', pCurr^.Salary:8:2);

pCurr := pCurr^.pNext;

end;

end;

end.

Текст файла Unit2.pas:

unit Unit2;

Interface

uses Unit1;

type

MyList2Class = Class(MyList1Class)

public

procedure PrependItem(sName: string; Salary: double);

procedure PrependFromFile(sFileName: string);

end;

Implementation

procedure MyList2Class.PrependItem(sName: string; Salary: double);

var

pNew: pPersonType;

begin

if not AloneItem(sName, Salary, pNew) then

begin

pNew^.pNext := pHead;

pHead := pNew;

end;

end;

procedure MyList2Class.PrependFromFile(sFileName: string);

var

F: Text;

sName: string[40];

Salary: double;

begin

Assign(F, sFileName);

{$I-}

Reset(F);

{$I+}

if IOResult <> 0 then

begin

WriteLN('File ', sFileName, ' not found');

Halt;

end;

while not EOF(F) do

begin

Readln(F, sName);

Readln(F, Salary);

PrependItem(sName, Salary);

end;

end;

end.