2_4 finale

program Project2;
{$APPTYPE CONSOLE}
uses
   System.SysUtils, Math;
const
   FileCompositionError = 'Error! Your file is composed incorrectly. ';
   ReadFileError = 'Error! Flie contains invalid data. ';
   NoSuchFileError = 'Error! No such file. ';
   WriteError = 'Error! Check ''w'' permissions of this file. ';
type
   TDots = array of array [0..1] of Integer;

function EnterInputFileName() : string;
var
   Name : string;
begin
   Writeln('Enter input file name');
   Readln(Name);
   while not FileExists(Name) do
   begin
      Writeln(NoSuchFileError, 'Input file name again');
      Readln(Name);
   end;
   EnterInputFileName := Name;
end;

function EnterOutputFileName() : string;
var
   Name : string;
begin
   Writeln('Enter output file name');
   Readln(Name);
   EnterOutputFileName := Name;
end;

function ReadFile(var Dots : TDots; var InputFile : TextFile) : Boolean;
var
   IsValid : Boolean;
   //Dots : TDots;
   i : Integer;
begin
   i := 0;
   IsValid := True;
   while not EoF(InputFile) and IsValid do
      begin
         SetLength(Dots, i + 1);
         Read(InputFile, Dots[i][0]);
         if EoLN(InputFile) then
            IsValid := False;
         Read(InputFile, Dots[i][1]);
         if not EoLN(InputFile) then
            IsValid := False;
         Inc(i);
      end;
   ReadFile := IsValid;
end;

function GetAmount(var Dots : TDots) : Integer;
var
   Counter, i, j, LastIndex : Integer;
begin
   Counter := 0;
   LastIndex := High(Dots);
   for i := 0 to LastIndex do
      if (Dots[i][0] >= 0) and (Dots[i][1] >= 0) then
         Counter := Counter + 1;
   GetAmount := Counter;
end;

procedure OutputAnswer(Answer : Integer; OutputFileName : string);
var
   OutputFile : TextFile;
begin
   try
      AssignFile(OutputFile, OutputFileName);
      Rewrite(OutputFile);
      Writeln(Format('There are %d dots in the 1-st quarter', [Answer]));
      Writeln(OutputFile, Format('There are %d dots in the 1-st quarter', [Answer]));
   except
      Writeln(WriteError);
   end;
   CloseFile(OutputFile);
end;

procedure Main();
var
   Dots : TDots;
   //Dots2 : TDots;
   InputFileName, OutputFileName : string;
   InputFile, OutputFile : TextFile;
begin
   Writeln('This program can calculate how many dots are in the 1-st quarter');
   try
      InputFileName := EnterInputFileName();
      AssignFile(InputFile, InputFileName);
      Reset(InputFile);
      if ReadFile(Dots, InputFile) then
      begin
         OutputFileName := EnterOutputFileName();
         OutputAnswer(GetAmount(Dots), OutputFileName);
      end
      else
         Writeln(FileCompositionError);
   except
      Writeln(ReadFileError);
   end;
   CloseFile(InputFile);
   Readln;
end;

begin
   Main();
end.