unit WriteUnit;

interface

uses
    System.SysUtils, ListUnit, ReadUnit, StartUnit;

    procedure clearFile();
    procedure write(TelephoneNumber: TTelephoneNumber; Surname: TSurname;
                              Name: TName; FatherName: TPatronymic;
                              City: TCity; DateOfPay: TDateOfPay); overload;
    procedure write(SubscriberIndex: TNumber; TelephoneNumber: TTelephoneNumber;
                                    Surname: TSurname; Name: TName; FatherName: TPatronymic;
                                  City: TCity; DateOfPay: TDateOfPay); overload;
    function toTelephoneNumber(Data: string): TTelephoneNumber;
    function toSurname(Data: string): TSurname;
    function toName(Data: string): TName;
    function toPatronymic(Data: string): TPatronymic;
    function toCity(Data: string): TCity;
    function toDateOfPay(StartDate: TDate; Data: integer): TDateOfPay;
    procedure deleteSubscriber(NumberOfSubscriber: TNumber);
    procedure removeDeleters();

implementation

uses
    DateUtils, Math;

procedure clearFile();
var
    SourceFile: TBinaryFile;
begin
    assign(SourceFile, getCurrentDir + '\' + FILE_NAME);
    rewrite(SourceFile);
    closeFile(SourceFile);
end;

procedure removeDeleters();
const
    TEMP_FILE_NAME = 'TempFile.bin';
var
    SourceFile, TempFile: TBinaryFile;
    OneByte: ansichar;
    BufferArray: Array[1..ONLY_DATA_SIZE] of ansichar;
    offset: integer;
    Number: longWord;
begin
    assign(SourceFile, GetCurrentDir + '\' + FILE_NAME);
    assign(TempFile, GetCurrentDir + '\' + TEMP_FILE_NAME);
    Number := 0;
    rewrite(TempFile);
    reset(SourceFile);
    offset := START_SUBSCRIBER_OFFSET;
    while not EOF(SourceFile) do
    begin
        blockRead(SourceFile, OneByte, 1);
        if (OneByte <> DELETER) then
        begin
            Seek(SourceFile, Offset + 4);
            blockRead(SourceFile, BufferArray, ONLY_DATA_SIZE);
            blockWrite(TempFile, Number, 4);
            blockWrite(TempFile,  BufferArray, ONLY_DATA_SIZE);
            inc(Number);
        end;
        Offset := Offset + RECORD_SIZE;
        seek(SourceFile, Offset);
    end;
    closeFile(SourceFile);
    closeFile(TempFile);
    deleteFile(GetCurrentDir + '\' + FILE_NAME);
    RenameFile(GetCurrentDir + '\' + TEMP_FILE_NAME, GetCurrentDir + '\' + FILE_NAME);
end;

procedure write(TelephoneNumber: TTelephoneNumber; Surname: TSurname;
                                  Name: TName; FatherName: TPatronymic;
                                  City: TCity; DateOfPay: TDateOfPay);
const
    MAX_SUBSCRIBER_NUMBER = 9999999;
var
    SourceFile: TBinaryFile;
    SizeOfFile: integer;
    NumberOfRecord: LongWord;
    ArrayOfRecordNumber: TNumber;
begin
    assign(SourceFile, getCurrentDir + '\' + FILE_NAME);
    reset(SourceFile);
    SizeOfFile := fileSize(SourceFile) - START_SUBSCRIBER_OFFSET;
    NumberOfRecord := SizeOfFile div RECORD_SIZE;
    if NumberOfRecord < MAX_SUBSCRIBER_NUMBER then
    begin
        Seek(SourceFile, SizeOfFile);
        blockWrite(SourceFile, NumberOfRecord, NUMBER_LENGTH);
        blockWrite(SourceFile, TelephoneNumber, TELEPHONE_NUMBER_LENGTH);
        blockWrite(SourceFile, Surname, SURNAME_LENGTH);
        blockWrite(SourceFile, Name, NAME_LENGTH);
        blockWrite(SourceFile, FatherName, PATRONYMIC_LENGTH);
        blockWrite(SourceFile, City, CITY_LENGTH);
        blockWrite(SourceFile, DateOfPay, DATE_OF_PAY_LENGTH);
    end;
    closeFile(SourceFile);
end;

procedure write(SubscriberIndex: TNumber; TelephoneNumber: TTelephoneNumber;
                                    Surname: TSurname; Name: TName; FatherName: TPatronymic;
                                  City: TCity; DateOfPay: TDateOfPay);
var
    SourceFile: TBinaryFile;
    ArrayOfRecordNumber: TNumber;
begin
    assign(SourceFile, getCurrentDir + '\' + FILE_NAME);
    reset(SourceFile);
    seek(SourceFile, START_SUBSCRIBER_OFFSET + SubscriberIndex * RECORD_SIZE);
    blockWrite(SourceFile, SubscriberIndex, NUMBER_LENGTH);
    blockWrite(SourceFile, TelephoneNumber, TELEPHONE_NUMBER_LENGTH);
    blockWrite(SourceFile, Surname, SURNAME_LENGTH);
    blockWrite(SourceFile, Name, NAME_LENGTH);
    blockWrite(SourceFile, Fathername, PATRONYMIC_LENGTH);
    blockWrite(SourceFile, City, CITY_LENGTH);
    blockWrite(SourceFile, DateofPay, DATE_OF_PAY_LENGTH);
    closeFile(SourceFile);
end;

procedure deleteSubscriber(NumberOfSubscriber: TNumber);
const
    DELETER: ansichar = '/';
var
    SourceFile: TBinaryFile;
    Offset: integer;
    NumberOfRecord: LongWord;
    ArrayOfRecordNumber: TNumber;
    DeleterArray: array[1..RECORD_SIZE] of ansichar;
begin
    fillchar(DeleterArray, RECORD_SIZE, DELETER);
    assign(SourceFile, getCurrentDir + '\' + FILE_NAME);
    reset(SourceFile);
    Offset := NumberOfSubscriber * RECORD_SIZE;
    seek(SourceFile, Offset);
    blockWrite(SourceFile, DeleterArray, RECORD_SIZE);
    closeFile(SourceFile);
end;

function toTelephoneNumber(Data: string): TTelephoneNumber;
var
    ResultArray: TTelephoneNumber;
    i: integer;
begin
    i := 1;
    while i <= length(Data) do
    begin
        ResultArray[i] := ansichar(Data[i]);
        inc(i);
    end;
    while i <= TELEPHONE_NUMBER_LENGTH do
    begin
        ResultArray[i] := ' ';
        inc(i);
    end;
    Result := ResultArray;
end;

function toSurname(Data: string): TSurname;
var
    ResultArray: TSurname;
    i: integer;
begin
    i := 1;
    while i <= length(Data) do
    begin
        ResultArray[i] := ansichar(Data[i]);
        inc(i);
    end;
    while i <= SURNAME_LENGTH do
    begin
        ResultArray[i] := ' ';
        inc(i);
    end;
    Result := ResultArray;
end;

function toName(Data: string): TName;
var
    ResultArray: TName;
    i: integer;
begin
    i := 1;
    while i <= length(Data) do
    begin
        ResultArray[i] := AnsiChar(Data[i]);
        inc(i);
    end;
    while i <= NAME_LENGTH do
    begin
        ResultArray[i] := ' ';
        inc(i);
    end;
    Result := ResultArray;
end;

function toPatronymic(Data: string): TPatronymic;
var
    ResultArray: TPatronymic;
    i: integer;
begin
    i := 1;
    while i <= length(Data) do
    begin
        ResultArray[i] := AnsiChar(Data[i]);
        inc(i);
    end;
    while i <= PATRONYMIC_LENGTH do
    begin
        ResultArray[i] := ' ';
        inc(i);
    end;
    Result := ResultArray;
end;

function toCity(Data: string): TCity;
var
    ResultArray: TCity;
    i: integer;
begin
    i := 1;
    while i <= length(Data) do
    begin
        ResultArray[i] := AnsiChar(Data[i]);
        inc(i);
    end;
    while i <= CITY_LENGTH do
    begin
        ResultArray[i] := ' ';
        inc(i);
    end;
    Result := ResultArray;
end;

function toDateOfPay(StartDate: TDate; Data: integer): TDateOfPay;
const
    FIRST_DOT = 3;
    SECOND_DOT = 6;
    MAX_DATE_STR = '23.11.9999';
var
    ResultArray: TDateOfPay;
    i, j: integer;
    NewDate: TDate;
    NewDateString: string;
    MaxDate: TDate;
begin
    MaxDate := strToDate(MAX_DATE_STR);
    NewDate := incDay(StartDate, Round(Data/(ServiceCost / 30 )));
    NewDateString := dateToStr(NewDate);
    j := 1;
    if (CompareDate(NewDate, MaxDate) = 1) then
        NewDateString := dateToStr(StartDate);
    for i := 1 to (DATE_OF_PAY_LENGTH + 2) do
    begin
        if (i <> FIRST_DOT) and (i <> SECOND_DOT) then
        begin
            ResultArray[j] := ansichar(NewDateString[i]);
            inc(j)
        end
        else
            ResultArray[i] := ansichar(0);
    end;
    Result := ResultArray;
end;

end.

unit ListUnit;

interface

uses
    System.SysUtils, Vcl.ExtCtrls;

const
    TELEPHONE_NUMBER_LENGTH = 13;
    SURNAME_LENGTH = 14;
    NAME_LENGTH = 11;
    PATRONYMIC_LENGTH = 14;
    CITY_LENGTH = 11;
    DATE_OF_PAY_LENGTH = 8;
    NUMBER_LENGTH = 4;
    RECORD_SIZE = TELEPHONE_NUMBER_LENGTH + SURNAME_LENGTH + NAME_LENGTH +
                 PATRONYMIC_LENGTH + CITY_LENGTH + DATE_OF_PAY_LENGTH + NUMBER_LENGTH;
    ONLY_DATA_SIZE = TELEPHONE_NUMBER_LENGTH + SURNAME_LENGTH + NAME_LENGTH +
                 PATRONYMIC_LENGTH + CITY_LENGTH + DATE_OF_PAY_LENGTH;

type

    TTelephoneNumber = array[1..TELEPHONE_NUMBER_LENGTH] of AnsiChar;
    TSurname = array[1..SURNAME_LENGTH] of AnsiChar;
    TName = array[1..NAME_LENGTH] of AnsiChar;
    TPatronymic = array[1..PATRONYMIC_LENGTH] of AnsiChar;
    TCity = array[1..CITY_LENGTH] of AnsiChar;
    TDateOfPay = array[1..DATE_OF_PAY_LENGTH] of AnsiChar;
    TNumberOfDays = integer;
    TNumber = longWord;
    TSubscriberPointer = ^TSubscriber;
    TCompareMethod = function(Previous, Next: TSubscriberPointer): boolean of object;

    TSubscriber = record
        next: TSubscriberPointer;
        telephoneNumber: TTelephoneNumber;
        surname: TSurname;
        name: TName;
        patronymic: TPatronymic;
        city: TCity;
        numberOfDays: TNumberOfDays;
        number: TNumber;
    end;

    TRequiredSubscriber = record
        telephoneNumber, surname, name, patronymic, city: string;
        numberOfDays: TNumberOfDays;
        number: TNumber;
    end;

    TSubscriberList = class
        private
            Header: TSubscriberPointer;
        public
            function getHeader(): TSubscriberPointer;
            constructor NewSubscriberList();
            procedure add(CurrentTelephoneNumber: TTelephoneNumber;
              CurrentSurname: TSurname; CurrentName: TName;
              CurrentFatherName: TPatronymic; CurrentCity: TCity;
              CurrentNumberOfDays: TNumberOfDays; CurrentNumber: TNumber);
            procedure deleteList();
            function length(): integer;
            function IsEmpty(): boolean;
            function getLastPosition(): TSubscriberPointer;
            procedure sort(CompareMethod: TCompareMethod);
            class function compareByTelephoneNumber(Previous,
              Next: TSubscriberPointer): boolean;
            class function compareBySurname(Previous,
              Next: TSubscriberPointer): boolean;
            class function compareByName(Previous,
              Next: TSubscriberPointer): boolean;
            class function compareByPatronymic(Previous,
              Next: TSubscriberPointer): boolean;
            class function compareByCity(Previous,
              Next: TSubscriberPointer): boolean;
            class function compareByDate(Previous,
              Next: TSubscriberPointer): boolean;
            class procedure QuckSort(var headRef: TSubscriberPointer; CompareMethod: TCompareMethod);
            class function getTail(Node: TSubscriberPointer): TSubscriberPointer;
            class function quickSortRecur(head: TSubscriberPointer;
                                        fin: TSubscriberPointer; CompareMethod: TCompareMethod): TSubscriberPointer;
            class function partition(head: TSubscriberPointer; Fin: TSubscriberPointer;
                       var NewHead: TSubscriberPointer;
                       var NewTail: TSubscriberPointer; CompareMethod: TCompareMethod): TSubscriberPointer;
    end;

implementation

uses
    EditUnit, ReadUnit;

constructor TSubscriberList.NewSubscriberList();
begin
    new(Header);
    Header^.next := nil;
end;

function TSubscriberList.IsEmpty(): Boolean;
begin
    Result := (Header^.next = nil);
end;

function TSubscriberList.getHeader(): TSubscriberPointer;
begin
    Result := Self.Header;
end;

function TSubscriberList.length(): integer;
var
    ListLength: integer;
    PTemp: TSubscriberPointer;
begin
    PTemp := getHeader();
    ListLength := 0;
    while (PTemp^.next <> nil) do
    begin
        PTemp := PTemp^.next;
        inc(ListLength);
    end;
    Result := ListLength;
end;

function TSubscriberList.getLastPosition(): TSubscriberPointer;
var
    PTemp: TSubscriberPointer;
begin
    PTemp := getHeader();
    while (PTemp^.next <> nil) do
        PTemp := PTemp^.next;
    Result := PTemp;
end;

procedure TSubscriberList.add(CurrentTelephoneNumber: TTelephoneNumber; CurrentSurname: TSurname;
                              CurrentName: TName; CurrentFatherName: TPatronymic; CurrentCity: TCity;
                              CurrentNumberOfDays: TNumberOfDays; CurrentNumber: TNumber);
var
    PLastSubscriber: TSubscriberPointer;
begin
    PLastSubscriber := getLastPosition();
    new(PLastSubscriber^.next);
    PLastSubscriber := PLastSubscriber^.next;
    PLastSubscriber^.number := CurrentNumber;
    PLastSubscriber^.telephoneNumber := CurrentTelephoneNumber;
    PLastSubscriber^.surname := CurrentSurname;
    PLastSubscriber^.name := CurrentName;
    PLastSubscriber^.patronymic := CurrentFatherName;
    PLastSubscriber^.city := CurrentCity;
    PLastSubscriber^.numberOfDays := CurrentNumberOfDays;
    PLastSubscriber^.next := nil;
end;

procedure TSubscriberList.deleteList();
var
    PDeleter: TSubscriberPointer;
    PTemp: TSubscriberPointer;
begin
    PTemp := Header^.next;;
    while PTemp <> nil do
    begin
        PDeleter := PTemp;
        PTemp := PTemp^.next;
        dispose(PDeleter);
    end;
    Header^.next := nil;
end;

class function TSubscriberList.compareByTelephoneNumber(Previous, Next: TSubscriberPointer): boolean;
begin
    Result := (Previous^.telephoneNumber > Next^.telephoneNumber);
end;

class function TSubscriberList.compareBySurname(Previous, Next: TSubscriberPointer): boolean;
begin
    Result := (Previous^.surname > Next^.surname);
end;

class function TSubscriberList.compareByName(Previous, Next: TSubscriberPointer): boolean;
begin
    Result := (Previous^.name > Next^.name);
end;

class function TSubscriberList.compareByPatronymic(Previous, Next: TSubscriberPointer): boolean;
begin
    Result := (Previous^.patronymic > Next^.patronymic);
end;

class function TSubscriberList.compareByCity(Previous, Next: TSubscriberPointer): boolean;
begin
    Result := (Previous^.city > Next^.city);
end;

class function TSubscriberList.compareByDate(Previous, Next: TSubscriberPointer): boolean;
begin
    Result := (Previous^.numberOfDays > Next^.numberOfDays);
end;


class function TSubscriberList.getTail(Node: TSubscriberPointer): TSubscriberPointer;
begin
    while (Node <> nil) and (Node^.next <> nil) do
        Node := Node^.next;
    Result := Node;
end;

class function TSubscriberList.partition(head: TSubscriberPointer; Fin: TSubscriberPointer;
                       var NewHead: TSubscriberPointer;
                       var NewTail: TSubscriberPointer; CompareMethod: TCompareMethod): TSubscriberPointer;
var
    Pivot: TSubscriberPointer;
    Previous: TSubscriberPointer;
    Current: TSubscriberPointer;
    Tail: TSubscriberPointer;
    Temp: TSubscriberPointer;
begin
    Pivot := Fin;
    Previous := nil;
    Current := head;
    Tail := Pivot;
    while (Current <> Pivot) do
    begin
        if CompareMethod(Pivot, Current) then
        begin
            if (newHead = nil) then
                newHead := Current;
            Previous := Current;
            Current := Current^.next;
        end
        else
        begin
            if (Previous <> nil) then
                Previous^.next := Current^.next;
            Temp := Current^.next;
            Current^.next := nil;
            Tail^.next := Current;
            Tail := Current;
            Current := Temp;
        end;
    end;
    if (NewHead = nil) then
        NewHead := Pivot;
    NewTail := Tail;
    Result := Pivot;
end;

class function TSubscriberList.quickSortRecur(head: TSubscriberPointer;
                 fin: TSubscriberPointer; CompareMethod: TCompareMethod): TSubscriberPointer;
var
    NewHead: TSubscriberPointer;
    NewEnd: TSubscriberPointer;
    tmp: TSubscriberPointer;
    pivot: TSubscriberPointer;
begin
    // base condition
    if ((not (head <> nil)) or (head = fin)) then
        Result := head
    else
    begin
        newHead := nil;
        newEnd := nil;
    // Partition the list, newHead and newEnd will be
    // updated by the partition function
        pivot := partition(head, fin, newHead, newEnd, CompareMethod);
    // If pivot is the smallest element - no need to recur
    // for the left part.
        if (newHead <> pivot) then
        begin
            // Set the node before the pivot node as nullptr
            tmp := newHead;
            while (tmp^.next <> pivot) do
                tmp := tmp^.next;
            tmp^.next := nil;
            newHead := quickSortRecur(newHead, tmp,CompareMethod);
            tmp := getTail(newHead);
            tmp^.next := pivot;
        end;
    pivot^.next := quickSortRecur(pivot^.next, newEnd, CompareMethod);
    Result := newHead;
    end;
end;

procedure TSubscriberList.Sort(CompareMethod: TCompareMethod);
begin
    QuckSort(Self.getHeader^.next, CompareMethod);
end;

class procedure TSubscriberList.QuckSort(var headRef: TSubscriberPointer; CompareMethod: TCompareMethod);
var
    Tail: TSubscriberPointer;
begin
    Tail := getTail(headRef);
    headRef := quickSortRecur(headRef, Tail, CompareMethod);
end;

end.

unit ReadUnit;

interface

uses
    System.SysUtils, ListUnit, EditUnit, DateUtils;

const
    PathToFile = 'C:\t\SubscribersFile.bin';
    FILE_NAME = 'SubscribersFile.bin';
    DELETER: ansichar = '/';
    START_SUBSCRIBER_OFFSET: LongWord = 0;

type
    TBinaryFile = file of byte;

    procedure readSubscribers(var RequiredSubscriber: TRequiredSubscriber);
    function getSubscriber(Index: longWord; var DateString: string): TSubscriber;
    function isEqual(RequiredString: string; var CurrentArray: array of AnsiChar): boolean;
    function isExist(var RequiredSubscriber: TRequiredSubscriber; var SameSubscriberIndex: integer): Boolean;
    function isFileEmpty(): Boolean;
    function dateArrayToString(var DateOfPayArray: TDateOfPay): string;
    function dateToNumber(var DateOfPayArray: TDateOfPay): TNumberOfdays;
    function isRequiredData(var SourceFile: TBinaryFile; var RequiredString: string;
                                      var TelephoneNumberArray: TTelephoneNumber): boolean; overload;
    function isRequiredData(var SourceFile: TBinaryFile; var RequiredString: string;
                                      var SurnameArray: TSurname): boolean; overload;
    function isRequiredData(var SourceFile: TBinaryFile; var RequiredString: string;
                                      var NameArray: TName): boolean; overload;
    function isRequiredData(var SourceFile: TBinaryFile; var RequiredString: string;
                                      var FathernameArray: TPatronymic): boolean; overload;
    function isRequiredData(var SourceFile: TBinaryFile; var RequiredString: string;
                                      var CityArray: TCity): boolean; overload;
    function isRequiredSubscriber(var SourceFile: TBinaryFile; var TelephoneNumberArray: TTelephoneNumber;
                                var SurnameArray: TSurname; var NameArray: TName;
                                  var PatromynicArray: TPatronymic; var CityArray: TCity;
                                  var RequiredSubscriber: TRequiredSubscriber): boolean;

implementation

function dateArrayToString(var DateOfPayArray: TDateOfPay): string;
begin
    Result := copy(DateOfPayArray, 1, 2) + '.' + copy(DateOfPayArray, 3, 2) + '.' + copy(DateOfPayArray, 5, 4);
end;

function dateToNumber(var DateOfPayArray: TDateOfPay): TNumberOfdays;
var
    NumberOfDaysLeft: integer;
    WritenTime, NowTime: TDateTime;
    StringTime: string;
    Difference: TNumberOfDays;
    DayDifferece: TNumberOfDays;
    ComparisonResult: integer;
begin
    StringTime := dateArrayToString(DateOfPayArray);
    WritenTime := strToDate(StringTime);
    NowTime := Now();
    ComparisonResult := compareDate(WritenTime, NowTime);
    DayDifferece := daysBetween(WritenTime, NowTime);
    Difference := DayDifferece * ComparisonResult;
    Result := Difference;
end;

procedure readSubscribers(var RequiredSubscriber: TRequiredSubscriber);
var
    SourceFile: TBinaryFile;
    TelephoneNumberArray: TTelephoneNumber;
    SurnameArray: TSurname;
    NameArray: TName;
    PatromynicArray: TPatronymic;
    CityArray: TCity;
    DateofPayArray: TDateOfPay;
    Number: TNumber;
    CurrentOffset, Offset: integer;
    OneByte: ansichar;
    NumberOfDays: longWord;
begin
    assign(SourceFile, getCurrentDir + '\' + FILE_NAME);
    reset(SourceFile);
    Offset := START_SUBSCRIBER_OFFSET;
    Seek(SourceFile, Offset);
    while not EOF(SourceFile) do
    begin
        blockRead(SourceFile, OneByte, 1);
        if OneByte <> DELETER then
        begin
            Seek(SourceFile, Offset);
            blockRead(SourceFile, Number, NUMBER_LENGTH);
            if isRequiredSubscriber(SourceFile, TelephoneNumberArray,
              SurnameArray, NameArray, PatromynicArray, CityArray,
              RequiredSubscriber) then
            begin
                blockRead(SourceFile, DateOfPayArray, DATE_OF_PAY_LENGTH);
                NumberOfDays := dateToNumber(DateOfPayArray);
                SubscriberList.add(TelephoneNumberArray, SurnameArray,
                  NameArray, PatromynicArray, CityArray, NumberOfDays, Number);
            end;
        end;
        Offset := Offset + RECORD_SIZE;
        Seek(SourceFile, Offset);
    end;
    close(SourceFile);
end;

function getSubscriber(Index: longWord; var DateString: string): TSubscriber;
var
    SourceFile: TBinaryFile;
    Offset: integer;
    CurrentSubscriber: TSubscriber;
    DateOfPayArray: TDateOfPay;
    NumberOfDays: longWord;
begin
     assign(SourceFile, getCurrentDir + '\' + FILE_NAME);
     reset(SourceFile);
     Offset := START_SUBSCRIBER_OFFSET + RECORD_SIZE * Index + NUMBER_LENGTH;
     Seek(SourceFile, Offset);
     blockRead(SourceFile, CurrentSubscriber.telephoneNumber, TELEPHONE_NUMBER_LENGTH);
     blockRead(SourceFile, CurrentSubscriber.surname, SURNAME_LENGTH);
     blockRead(SourceFile, CurrentSubscriber.name, NAME_LENGTH);
     blockRead(SourceFile, CurrentSubscriber.patronymic, PATRONYMIC_LENGTH);
     blockRead(SourceFile, CurrentSubscriber.city, CITY_LENGTH);
     blockRead(SourceFile, DateOfPayArray, DATE_OF_PAY_LENGTH);
     DateString := dateArrayToString(DateOfPayArray);
     close(SourceFile);
     Result := CurrentSubscriber;
end;

function isExist(var RequiredSubscriber: TRequiredSubscriber; var SameSubscriberIndex: integer): boolean;
var
    IsExist: boolean;
    SourceFile: TBinaryFile;
    TelephoneNumberArray: TTelephoneNumber;
    SurnameArray: TSurname;
    NameArray: TName;
    PatromynicArray: TPatronymic;
    CityArray: TCity;
    DateofPayArray: TDateOfPay;
    Number: TNumber;
    CurrentOffset, Offset: integer;
    OneByte: ansichar;
begin
    assign(SourceFile, getCurrentDir + '\' + FILE_NAME);
    reset(SourceFile);
    Offset := START_SUBSCRIBER_OFFSET;
    Seek(SourceFile, Offset);
    IsExist := false;
    while (not EOF(SourceFile)) and (not IsExist) do
    begin
        blockRead(SourceFile, OneByte, 1);
        if OneByte <> DELETER then
        begin
            Seek(SourceFile, Offset);
            blockRead(SourceFile, Number, NUMBER_LENGTH);
              if isRequiredSubscriber(SourceFile, TelephoneNumberArray,
                        SurnameArray, NameArray, PatromynicArray, CityArray, RequiredSubscriber) then
              begin
                  IsExist := true;
                  SameSubscriberIndex := Number;
              end;
        end;
        Offset := Offset + RECORD_SIZE;
        Seek(SourceFile, Offset);
    end;
    close(SourceFile);
    Result := IsExist;
end;

function isRequiredSubscriber(var SourceFile: TBinaryFile; var TelephoneNumberArray: TTelephoneNumber;
                                var SurnameArray: TSurname; var NameArray: TName;
                                  var PatromynicArray: TPatronymic; var CityArray: TCity;
                                  var RequiredSubscriber: TRequiredSubscriber): boolean;
begin
    Result := isRequiredData(SourceFile, RequiredSubscriber.telephoneNumber, TelephoneNumberArray)
              and isRequiredData(SourceFile, RequiredSubscriber.surname, SurnameArray)
              and isRequiredData(SourceFile, RequiredSubscriber.name, NameArray)
              and isRequiredData(SourceFile, RequiredSubscriber.patronymic, PatromynicArray)
              and isRequiredData(SourceFile, RequiredSubscriber.city, CityArray);
end;

function isFileEmpty(): Boolean;
var
    SourceFile: TBinaryFile;
    IsEmpty: boolean;
    SizeOfFile: integer;
begin
    assign(SourceFile, getCurrentDir + '\' + FILE_NAME);
    Reset(SourceFile);
    SizeOfFile := FileSize(SourceFile);
    close(SourceFile);
    Result := (SizeOfFile = 0);
end;

function isEqual(RequiredString: string; var CurrentArray: array of AnsiChar): Boolean;
var
    IsSame: boolean;
    i: integer;
begin
    IsSame := true;
    i := 1;
    while IsSame and (i <= length(RequiredString)) do
        if (RequiredString[i] <> char(CurrentArray[i - 1])) then
            IsSame := false
        else
            inc(i);
    Result := IsSame;
end;

function IsRequiredData(var SourceFile: TBinaryFile; var RequiredString: string;
                                          var TelephoneNumberArray: TTelephoneNumber): boolean;
var
    IsRequiredData: boolean;
begin
    blockRead(SourceFile, TelephoneNumberArray, TELEPHONE_NUMBER_LENGTH);
    Result := isEqual(RequiredString, TelephoneNumberArray);
end;

function IsRequiredData(var SourceFile: TBinaryFile; var RequiredString: string;
                                          var SurnameArray: TSurname): boolean;
var
    IsRequiredData: boolean;
begin
    blockRead(SourceFile, SurnameArray, SURNAME_LENGTH);
    Result := isEqual(RequiredString, SurnameArray);
end;

function IsRequiredData(var SourceFile: TBinaryFile; var RequiredString: string;
                                          var NameArray: TName): boolean;
var
    IsRequiredData: boolean;
begin
    blockRead(SourceFile, NameArray, NAME_LENGTH);
    Result := isEqual(RequiredString, NameArray);
end;

function IsRequiredData(var SourceFile: TBinaryFile; var RequiredString: string;
                                          var FathernameArray: TPatronymic): boolean;
var
    IsRequiredData: boolean;
begin
    blockRead(SourceFile, FathernameArray, PATRONYMIC_LENGTH);
    Result := isEqual(RequiredString, FathernameArray);
end;

function IsRequiredData(var SourceFile: TBinaryFile; var RequiredString: string;
                                          var CityArray: TCity): boolean;
var
    IsRequiredData: boolean;
begin
    blockRead(SourceFile, CityArray, CITY_LENGTH);
    Result := isEqual(RequiredString, CityArray);
end;

end.

unit CorrectUnit;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.Menus, Vcl.Samples.Spin, DateUtils, AddUnit, EditUnit;

type
  TCorrectForm = class(TForm)
    NameLabel: TLabel;
    SurnameLabel: TLabel;
    PatronumicLabel: TLabel;
    CityLabel: TLabel;
    TelephoneLabel: TLabel;
    TelephoneEdit: TEdit;
    NameEdit: TEdit;
    SurnameEdit: TEdit;
    PatronymicEdit: TEdit;
    CItyEdit: TEdit;
    TaskLabel: TLabel;
    SaveButton: TButton;
    MainMenu: TMainMenu;
    InstructionMenu: TMenuItem;
    PayLabel: TLabel;
    ResetButton: TButton;
    DateLabel: TLabel;
    DateOfPayLabel: TLabel;
    PaySpinEdit: TSpinEdit;
    SuccessLabel: TLabel;
    WrongDataLabel: TLabel;
    UpdateMenu: TMenuItem;
    SubscriberExistsLabel: TLabel;
    procedure ResetButtonClick(Sender: TObject);
    procedure TurnLabelsOff();
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure FormShow(Sender: TObject);
    procedure SaveButtonClick(Sender: TObject);
    procedure showSavedInfo();
    procedure UpdateMenuClick(Sender: TObject);
    procedure deleteSpaces();
    procedure InstructionMenuClick(Sender: TObject);
    procedure TelephoneEditKeyPress(Sender: TObject; var Key: Char);
    procedure FormKeyPress(Sender: TObject; var Key: Char);
    procedure TextEditKeyPress(Sender: TObject; var Key: Char);
    function areEditsCorrect(): boolean;
    procedure SomeEditChange(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  CorrectForm: TCorrectForm;

implementation

{$R *.dfm}

uses
    ReadUnit, WriteUnit, ListUnit;


procedure TCorrectForm.ResetButtonClick(Sender: TObject);
var
    TelephoneNumber: TTelephoneNumber;
    Surname: TSurname;
    Name: TName;
    Patronymic: TPatronymic;
    City: TCity;
    DateofPay: TDateOfPay;
begin
    DateOfPayLabel.caption := dateToStr(Now);
    PaySpinEdit.Value := 0;
    turnLabelsOff();
end;

function TCorrectForm.areEditsCorrect(): boolean;

begin
    Result := (EditForm.IsCorrectNumberData(TelephoneEdit) and EditForm.IsCorrectTextData(SurnameEdit) and
               EditForm.IsCorrectTextData(NameEdit) and EditForm.IsCorrectTextData(PatronymicEdit) and
               EditForm.IsCorrectTextData(CityEdit) and
               AddForm.areEditsFilled(TelephoneEdit, SurnameEdit, NameEdit, PatronymicEdit, CityEdit));
end;

procedure TCorrectForm.SaveButtonClick(Sender: TObject);
var
    TelephoneNumber: TTelephoneNumber;
    Surname: TSurname;
    Name: TName;
    Patronymic: TPatronymic;
    City: TCity;
    DateofPay: TDateOfPay;
    SameSubscriberIndex: integer;
    RequiredSubscriber: TRequiredSubscriber;
begin
    SameSubscriberIndex := -1;
    TelephoneNumber := toTelephoneNumber(TelephoneEdit.text);
    Surname := toSurname(SurnameEdit.Text);
    Name := toName(NameEdit.Text);
    Patronymic := toPatronymic(PatronymicEdit.Text);
    City := toCity(CityEdit.Text);
    DateOfPay := toDateOfPay(strToDate(DateOfPayLabel.Caption), PaySpinEdit.Value);
    PaySpinEdit.Value := 0;
    EditForm.getRequiredSubscriber(RequiredSubscriber,  TelephoneEdit.text, SurnameEdit.text, NameEdit.text,
                                PatronymicEdit.text, CityEdit.text);
    if isExist(RequiredSubscriber, SameSubscriberIndex)
        and (not(SubscriberIndex = SameSubscriberIndex)) then
        SubscriberExistsLabel.Visible := true
    else
    begin
        if (not areEditsCorrect()) then
            WrongDataLabel.Visible := true
        else
        begin
            write(SubscriberIndex, TelephoneNumber, Surname, Name, Patronymic, City,
                  DateofPay);
            showSavedInfo();
            SuccessLabel.Visible := true;
        end;
    end;
end;

procedure TCorrectForm.FormClose(Sender: TObject; var Action: TCloseAction);
begin
    EditForm.enabled := true;
    PaySpinEdit.value := 0;
end;

procedure TCorrectForm.FormKeyPress(Sender: TObject; var Key: Char);
begin
    if key = #27 then
        AddForm.Close()
    else
        if Key = #13 then
            SaveButtonClick(Sender);
end;

procedure TCorrectForm.FormShow(Sender: TObject);
begin
    showSavedInfo();
end;

procedure TCorrectForm.InstructionMenuClick(Sender: TObject);
begin
    MessageDlg('This is the correction window. Here you can change current subscriber''s data.'
                            + #13#10 + 'After clicking "Save" you will see label with result:'
                            + #13#10 + '1. "Changes saved" - you succesfully changed.'
                            + #13#10 + '2. "Subscriber exists" - subscriber with this data already exists.'
                            + #13#10 + '3. "Wront input" - some fileds are filled incorrectly.' + #13#10 +
                            'Right input:' + #13#10 +
                            'a) Telephone number field: first char - "+" or digit and next are digits; length = 13;'
                            + #13#10 + 'b) Text fields: first char - big letter and next are small letters. Length:'
                            + #13#10 + 'City -11, Surname - 14, Name - 11, Patronymic - 14.' + #13#10
                            + #13#10 + 'Field can not be empty.' + #13#10
                            + #13#10 + 'In the field "Payment" you should input the amount of money paid'
                            + #13#10 + 'Use menu button "Update" or press "ctrl + r" to show saved data;'
                            + #13#10 + 'Use button "Reset payment" to change payment day for today''s date;'
                            + #13#10 + #13#10 + 'Press "ctrl + i" to open instruction;'
                            + #13#10 + 'Press "enter" to save changes;' +
                            #13#10 +  'Press "esc" to go back to edit widnow.', MtInformation, [mbOk], 0);
end;

procedure TCorrectForm.deleteSpaces();
var
    Edit: TEdit;
    i: integer;
    BufferString: string;
begin
    for Edit in [SurnameEdit, NameEdit, PatronymicEdit, TelephoneEdit, CityEdit] do
    begin
        BufferString := Edit.text;
        Edit.text := '';
        for i := 1 to length(BufferString) do
            if BufferString[i] <> ' ' then
                Edit.text := Edit.text + BufferString[i];
    end;
end;

procedure TCorrectForm.showSavedInfo();
var
    CurrentSubscriber: TSubscriber;
    DateString: string;
begin
    CurrentSubscriber := getSubscriber(SubscriberIndex, DateString);
    TelephoneEdit.text := CurrentSubscriber.telephoneNumber;
    SurnameEdit.text := CurrentSubscriber.surname;
    NameEdit.text := CurrentSubscriber.name;
    PatronymicEdit.text := CurrentSubscriber.patronymic;
    CityEdit.text := CurrentSubscriber.city;
    deleteSpaces;
    DateOfPayLabel.caption := DateString;
    PaySpinEdit.Value := 0;
    turnLabelsOff();
end;

procedure TCorrectForm.TextEditKeyPress(Sender: TObject; var Key: Char);
begin
    AddForm.TextEditKeyPress(Sender, Key);
end;

procedure TCorrectForm.SomeEditChange(Sender: TObject);
begin
    turnLabelsOff();
end;

procedure TCorrectForm.TelephoneEditKeyPress(Sender: TObject; var Key: Char);
begin
    AddForm.TelephoneKeyPress(Sender, Key);
end;

procedure TCorrectForm.TurnLabelsOff();
begin
    SuccessLabel.visible := false;
    WrongDataLabel.visible := false;
    SubscriberExistsLabel.visible := false;
end;

procedure TCorrectForm.UpdateMenuClick(Sender: TObject);
begin
    showSavedInfo();
end;

end.

unit AddUnit;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.Menus, Vcl.Samples.Spin, EditUnit;

type
  TAddForm = class(TForm)
    NameLabel: TLabel;
    SurnameLabel: TLabel;
    PatronymicLabel: TLabel;
    CityLabel: TLabel;
    DateLabel: TLabel;
    TelephoneLabel: TLabel;
    TelephoneEdit: TEdit;
    NameEdit: TEdit;
    SurnameEdit: TEdit;
    PatronymicEdit: TEdit;
    CItyEdit: TEdit;
    TaskLabel: TLabel;
    AddButton: TButton;
    MainMenu: TMainMenu;
    InstructionMenu: TMenuItem;
    SubscriberAddedLabel: TLabel;
    PaymentEdit: TSpinEdit;
    WrongDataLabel: TLabel;
    SubscriberExistsLabel: TLabel;
    procedure AddButtonClick(Sender: TObject);
    procedure SomeEditChange(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure turnLabelsOff();
    procedure InstructionMenuClick(Sender: TObject);
    procedure TextEditKeyPress(Sender: TObject; var Key: Char);
    procedure TelephoneKeyPress(Sender: TObject; var Key: Char);
    procedure FormKeyPress(Sender: TObject; var Key: Char);
    procedure FormShow(Sender: TObject);
    function areEditsFilled(TelephoneEdit, SurnameEdit, NameEdit, FathernameEdit, CityEdit: TEdit): boolean;
    function areEditsCorrect(): boolean;
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  AddForm: TAddForm;

implementation

{$R *.dfm}

uses
    ReadUnit, WriteUnit, ListUnit, StartUnit;

const
    BIG_LETTERS = ['A'..'Z'];
    SMALL_LETTERS = ['a'..'z'];
    DIGITS = ['0'..'9'];

procedure TAddForm.AddButtonClick(Sender: TObject);

var
    TelephoneNumber: TTelephoneNumber;
    Surname: TSurname;
    Name: TName;
    Patronymic: TPatronymic;
    City: TCity;
    DateofPay: TDateOfPay;
    Buff: integer;
    SameSubscriberIndex: integer;
    RequiredSubscriber: TRequiredSubscriber;
begin
    TelephoneNumber := toTelephoneNumber(TelephoneEdit.text);
    Surname := toSurname(SurnameEdit.Text);
    Name := toName(NameEdit.Text);
    Patronymic := toPatronymic(PatronymicEdit.Text);
    City := toCity(CityEdit.Text);
    buff := PaymentEdit.value;
    DateOfPay := toDateOfPay(Now, PaymentEdit.value);
    TurnLabelsOff();
    EditForm.getRequiredSubscriber(RequiredSubscriber,  TelephoneEdit.text, SurnameEdit.text, NameEdit.text,
                                PatronymicEdit.text, CityEdit.text);
    if isExist(RequiredSubscriber, SameSubscriberIndex) then
        SubscriberExistsLabel.Visible := true
    else
    begin
        if not areEditsCorrect() then
            WrongDataLabel.Visible := true
        else
        begin
            write(TelephoneNumber, Surname, Name, Patronymic, City, DateofPay);
            SubscriberAddedLabel.Visible := true;
        end;
    end;
end;


function TAddForm.areEditsFilled(TelephoneEdit, SurnameEdit, NameEdit, FathernameEdit, CityEdit: TEdit): boolean;

begin
    Result := ((TelephoneEdit.text <> '') and (SurnameEdit.text <> '') and (FathernameEdit.text <> '')
                and (NameEdit.text <> '') and (CityEdit.text <> ''));
end;

function TAddForm.areEditsCorrect(): boolean;

begin
    Result := (EditForm.IsCorrectNumberData(TelephoneEdit) and EditForm.IsCorrectTextData(SurnameEdit) and
               EditForm.IsCorrectTextData(NameEdit) and EditForm.IsCorrectTextData(PatronymicEdit) and
               EditForm.IsCorrectTextData(CityEdit) and
               areEditsFilled(TelephoneEdit, SurnameEdit, NameEdit, PatronymicEdit, CityEdit));
end;

procedure TAddForm.FormClose(Sender: TObject; var Action: TCloseAction);

var
    Edit: TEdit;

begin
    EditForm.enabled := true;
    TurnLabelsOff();
    for Edit in [SurnameEdit, NameEdit, PatronymicEdit, TelephoneEdit, CityEdit] do
        Edit.text := '';
    PaymentEdit.value := 0;
end;

procedure TAddForm.FormKeyPress(Sender: TObject; var Key: Char);
begin
    if key = #27 then
        AddForm.Close()
    else
        if Key = #13 then
            AddButtonClick(Sender);
end;

procedure TAddForm.FormShow(Sender: TObject);
var
    Edit: TEdit;
begin
    for Edit in [SurnameEdit, NameEdit, PatronymicEdit, TelephoneEdit, CityEdit] do
        Edit.text := '';
end;

procedure TAddForm.InstructionMenuClick(Sender: TObject);
begin
    MessageDlg('This is the add window. Here you can add a new subscriber to database.' + #13#10
                            + #13#10 + 'After clicking "add" you will see label with result:'
                            + #13#10 + '1. "Subscriber added" - you succesfully added a new person.'
                            + #13#10 + '2. "Subscriber exists" - subscriber with this data already exists.'
                            + #13#10 + '3. "Wront input" - some fileds are filled incorrectly.' + #13#10
                            + 'Right input:' + #13#10 +
                            'a) Telephone number field: first char - "+" or digit and next are digits; length = 13;'
                            + #13#10 + 'b) Text fields: first char - big letter and next are small letters. Length:'
                            + #13#10 + 'City - 11, Surname - 14, Name - 11, Patronymic - 14.'
                            + #13#10 + 'Field can not be empty.' + #13#10
                            + #13#10 + 'In the field "Payment" you should input the amount of money paid'
                            + #13#10 + #13#10 + 'Press "ctrl + i" to open instruction;'
                            + #13#10 + 'Press "enter" to add subscriber;'
                            + #13#10 +  'Press "esc" to go back to edit widnow.', MtInformation, [mbOk], 0);
end;

procedure TAddForm.SomeEditChange(Sender: TObject);
begin
    turnLabelsOff();
end;

procedure TAddForm.TextEditKeyPress(Sender: TObject; var Key: Char);
begin
    if (Key <> #08) then
    begin
        if length((Sender as TEdit).text) = 0 then
        begin
            if not (Key in BIG_LETTERS) then
                Key := #0
        end
        else if not(Key in SMALL_LETTERS) then
            Key := #0;
    end;
end;

procedure TAddForm.TelephoneKeyPress(Sender: TObject; var Key: Char);
begin
    if (Key <> #08) then
    begin
        if length((Sender as TEdit).text) = 0 then
        begin
            if ((not(Key in DIGITS)) and (Key <> '+')) then
                Key := #0
        end
        else if not(Key in DIGITS) then
            Key := #0;
    end;
end;

procedure TAddForm.TurnLabelsOff();
begin
    SubscriberAddedLabel.Visible := false;
    SubscriberExistsLabel.Visible := false;
    WrongDataLabel.Visible := false;
end;

end.

unit AddUnit;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.Menus, Vcl.Samples.Spin, EditUnit;

type
  TAddForm = class(TForm)
    NameLabel: TLabel;
    SurnameLabel: TLabel;
    PatronymicLabel: TLabel;
    CityLabel: TLabel;
    DateLabel: TLabel;
    TelephoneLabel: TLabel;
    TelephoneEdit: TEdit;
    NameEdit: TEdit;
    SurnameEdit: TEdit;
    PatronymicEdit: TEdit;
    CItyEdit: TEdit;
    TaskLabel: TLabel;
    AddButton: TButton;
    MainMenu: TMainMenu;
    InstructionMenu: TMenuItem;
    SubscriberAddedLabel: TLabel;
    PaymentEdit: TSpinEdit;
    WrongDataLabel: TLabel;
    SubscriberExistsLabel: TLabel;
    procedure AddButtonClick(Sender: TObject);
    procedure SomeEditChange(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure turnLabelsOff();
    procedure InstructionMenuClick(Sender: TObject);
    procedure TextEditKeyPress(Sender: TObject; var Key: Char);
    procedure TelephoneKeyPress(Sender: TObject; var Key: Char);
    procedure FormKeyPress(Sender: TObject; var Key: Char);
    procedure FormShow(Sender: TObject);
    function areEditsFilled(TelephoneEdit, SurnameEdit, NameEdit, FathernameEdit, CityEdit: TEdit): boolean;
    function areEditsCorrect(): boolean;
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  AddForm: TAddForm;

implementation

{$R *.dfm}

uses
    ReadUnit, WriteUnit, ListUnit, StartUnit;

const
    BIG_LETTERS = ['A'..'Z'];
    SMALL_LETTERS = ['a'..'z'];
    DIGITS = ['0'..'9'];

procedure TAddForm.AddButtonClick(Sender: TObject);

var
    TelephoneNumber: TTelephoneNumber;
    Surname: TSurname;
    Name: TName;
    Patronymic: TPatronymic;
    City: TCity;
    DateofPay: TDateOfPay;
    Buff: integer;
    SameSubscriberIndex: integer;
    RequiredSubscriber: TRequiredSubscriber;
begin
    TelephoneNumber := toTelephoneNumber(TelephoneEdit.text);
    Surname := toSurname(SurnameEdit.Text);
    Name := toName(NameEdit.Text);
    Patronymic := toPatronymic(PatronymicEdit.Text);
    City := toCity(CityEdit.Text);
    buff := PaymentEdit.value;
    DateOfPay := toDateOfPay(Now, PaymentEdit.value);
    TurnLabelsOff();
    EditForm.getRequiredSubscriber(RequiredSubscriber,  TelephoneEdit.text, SurnameEdit.text, NameEdit.text,
                                PatronymicEdit.text, CityEdit.text);
    if isExist(RequiredSubscriber, SameSubscriberIndex) then
        SubscriberExistsLabel.Visible := true
    else
    begin
        if not areEditsCorrect() then
            WrongDataLabel.Visible := true
        else
        begin
            write(TelephoneNumber, Surname, Name, Patronymic, City, DateofPay);
            SubscriberAddedLabel.Visible := true;
        end;
    end;
end;


function TAddForm.areEditsFilled(TelephoneEdit, SurnameEdit, NameEdit, FathernameEdit, CityEdit: TEdit): boolean;

begin
    Result := ((TelephoneEdit.text <> '') and (SurnameEdit.text <> '') and (FathernameEdit.text <> '')
                and (NameEdit.text <> '') and (CityEdit.text <> ''));
end;

function TAddForm.areEditsCorrect(): boolean;

begin
    Result := (EditForm.IsCorrectNumberData(TelephoneEdit) and EditForm.IsCorrectTextData(SurnameEdit) and
               EditForm.IsCorrectTextData(NameEdit) and EditForm.IsCorrectTextData(PatronymicEdit) and
               EditForm.IsCorrectTextData(CityEdit) and
               areEditsFilled(TelephoneEdit, SurnameEdit, NameEdit, PatronymicEdit, CityEdit));
end;

procedure TAddForm.FormClose(Sender: TObject; var Action: TCloseAction);

var
    Edit: TEdit;

begin
    EditForm.enabled := true;
    TurnLabelsOff();
    for Edit in [SurnameEdit, NameEdit, PatronymicEdit, TelephoneEdit, CityEdit] do
        Edit.text := '';
    PaymentEdit.value := 0;
end;

procedure TAddForm.FormKeyPress(Sender: TObject; var Key: Char);
begin
    if key = #27 then
        AddForm.Close()
    else
        if Key = #13 then
            AddButtonClick(Sender);
end;

procedure TAddForm.FormShow(Sender: TObject);
var
    Edit: TEdit;
begin
    for Edit in [SurnameEdit, NameEdit, PatronymicEdit, TelephoneEdit, CityEdit] do
        Edit.text := '';
end;

procedure TAddForm.InstructionMenuClick(Sender: TObject);
begin
    MessageDlg('This is the add window. Here you can add a new subscriber to database.' + #13#10
                            + #13#10 + 'After clicking "add" you will see label with result:'
                            + #13#10 + '1. "Subscriber added" - you succesfully added a new person.'
                            + #13#10 + '2. "Subscriber exists" - subscriber with this data already exists.'
                            + #13#10 + '3. "Wront input" - some fileds are filled incorrectly.' + #13#10
                            + 'Right input:' + #13#10 +
                            'a) Telephone number field: first char - "+" or digit and next are digits; length = 13;'
                            + #13#10 + 'b) Text fields: first char - big letter and next are small letters. Length:'
                            + #13#10 + 'City - 11, Surname - 14, Name - 11, Patronymic - 14.'
                            + #13#10 + 'Field can not be empty.' + #13#10
                            + #13#10 + 'In the field "Payment" you should input the amount of money paid'
                            + #13#10 + #13#10 + 'Press "ctrl + i" to open instruction;'
                            + #13#10 + 'Press "enter" to add subscriber;'
                            + #13#10 +  'Press "esc" to go back to edit widnow.', MtInformation, [mbOk], 0);
end;

procedure TAddForm.SomeEditChange(Sender: TObject);
begin
    turnLabelsOff();
end;

procedure TAddForm.TextEditKeyPress(Sender: TObject; var Key: Char);
begin
    if (Key <> #08) then
    begin
        if length((Sender as TEdit).text) = 0 then
        begin
            if not (Key in BIG_LETTERS) then
                Key := #0
        end
        else if not(Key in SMALL_LETTERS) then
            Key := #0;
    end;
end;

procedure TAddForm.TelephoneKeyPress(Sender: TObject; var Key: Char);
begin
    if (Key <> #08) then
    begin
        if length((Sender as TEdit).text) = 0 then
        begin
            if ((not(Key in DIGITS)) and (Key <> '+')) then
                Key := #0
        end
        else if not(Key in DIGITS) then
            Key := #0;
    end;
end;

procedure TAddForm.TurnLabelsOff();
begin
    SubscriberAddedLabel.Visible := false;
    SubscriberExistsLabel.Visible := false;
    WrongDataLabel.Visible := false;
end;

end.