program Lab2_2;

{$APPTYPE CONSOLE}

uses
   SysUtils;

type
   TIntArray = array of Integer;
   TBoolArray = array of Boolean;

function CheckInput(): Integer;
var
   P: Integer;
   IsCorrectInput: Boolean;
begin
   IsCorrectInput := False;
   repeat
      try
         Write('Please, enter P: ');
         Readln(P);
         if P < 2 then
            Writeln('Invalid input! P must be natural number from 2 to ', High(Integer), '.')
         else
            IsCorrectInput := True;
      except
         Writeln('Invalid input! P must be natural number from 2 to ', High(Integer), '.');
      end;
   until IsCorrectInput;
   CheckInput := P;
end;


function ProduceBoolArray(P: Integer): TBoolArray;
var
   i: Integer;
   BoolArray: TBoolArray;
begin
   SetLength(BoolArray, P);
   for i := 2 to P do
      BoolArray[i] := False;
   ProduceBoolArray := BoolArray;
end;

function FindPrimeNumbers(BoolArray: TBoolArray; P: Integer; var PrimeAmount: Integer): TBoolArray;
var
   i, j: Integer;
begin
   PrimeAmount := 0;
   for i := 2 to P do
      if not BoolArray[i]  then
      begin
         j := i * 2;
         Inc(PrimeAmount);
         while (j <= P) do
         begin
            BoolArray[j] := True;
            j := j + i;
         end;
      end;
   FindPrimeNumbers := BoolArray;
end;

function TransformBoolArray(BoolArray: TBoolArray; P, PrimeAmount: Integer): TIntArray;
var
   IntArray: TIntArray;
   i, j: Integer;
begin
   j := 0;
   SetLength(IntArray, PrimeAmount);
   for i := 2 to P do
   begin
      if not BoolArray[i] then
      begin
         IntArray[j] := i;
         Inc(j);
      end;
   end;
   TransformBoolArray := IntArray;
end;

procedure OutputArray(IntArray: TIntArray; PrimeAmount: Integer);
var
   i: Integer;
begin
   Dec(PrimeAmount);
   for i := 0 to PrimeAmount do
      Write(IntArray[i],' ');
end;

procedure Main();
var
   P, PrimeAmount: Integer;
   IntArray: TIntArray;
   BoolArray: TBoolArray;
begin
   Writeln('This program shows all prime numbers from 2 to P.');
   Writeln('The range of input data is [2 to ', High(Integer), '].');
   P := CheckInput();
   BoolArray := ProduceBoolArray(P);
   BoolArray := FindPrimeNumbers(BoolArray, P, PrimeAmount);
   IntArray := TransformBoolArray(BoolArray, P, PrimeAmount);
   OutputArray(IntArray, PrimeAmount);
   Readln;
end;

begin
   Main();
end.