бинарный поиск

program searches;
uses crt,dos;
type longint_file=file of longint;
procedure files_names_query(var read_file,error:string; var search_value:longint);
var f:text;
  begin
    error:='';
    write('‘зЁвлў*Ґ¬л© д*©«: ');
    readln(read_file);
    assign(f,read_file);
    {$I-}
    reset(f);
    if (ioresult=0)
    then
      begin
        close(f);
        write('Ќ*室Ё¬®Ґ §**зҐ*ЁҐ=');
        readln(search_value);
      end
    else
      begin
        error:='ЋиЁЎЄ*: д*©« *Ґ бгйҐбвўгҐв.';
      end;
    {$I+}
  end;
function bin_search(left,right,search_value:longint;var f:longint_file):boolean;
var center,value,new_left,new_right,right_value,center_value:longint;
  begin
    if (left=right)
    then
      begin
        seek(f,left);
        read(f,value);
        if (value=search_value)
        then
          begin
            bin_search:=TRUE;
          end
        else
          begin
            bin_search:=FALSE;
          end;
      end
    else
      begin
        center:=((left+right) div 2)+1;
        seek(f,right);
        read(f,right_value);
        seek(f,center);
        read(f,center_value);
        if ((search_value>=center_value)and(search_value<=right_value))
        then
          begin
            new_left:=center;
            bin_search:=bin_search(new_left,right,search_value,f);
          end
        else
          begin
            new_right:=center-1;
            bin_search:=bin_search(left,new_right,search_value,f);
          end;
      end;
  end;
function search(read_file:string; search_value:longint):boolean;
var f:longint_file;
    finded:boolean;
    elements_count:longint;
  begin
    assign(f,read_file);
    reset(f);
    finded:=FALSE;
    elements_count:=filesize(f);
    finded:=bin_search(0,elements_count-1,search_value,f);
    close(f);
    search:=finded;
  end;
procedure writing_to_file(write_file:string;finded:boolean;begin_time:longint);
var f:text;
    hour,minutes,seconds,seconds100:word;
    end_time:longint;
    time:real;
  begin
    gettime(hour,minutes,seconds,seconds100);
    end_time:=minutes*60*100+seconds*100+seconds100;
    time:=(end_time-begin_time)/100;
    assign(f,write_file);
    rewrite(f);
    if (finded)
    then
      writeln(f,'ok')
    else
      writeln(f,'error');
    writeln(f,time:4:2);
    close(f);
  end;
procedure writing(finded:boolean; begin_time:longint);
  begin
    if (finded)
    then
      begin
        writeln('Element finded complete');
      end
    else
      begin
        writeln('Element not finded');
      end;
    readln;
  end;
var read_file,write_file,error,search_value_string:string;
    hour,minutes,seconds,seconds100:word;
    begin_time,search_value:longint;
    k:integer;
    result:boolean;
begin
  gettime(hour,minutes,seconds,seconds100);
  begin_time:=minutes*60*100+seconds*100+seconds100;
  if (paramstr(1)<>''){Ґб«Ё Ґбвм Ї*а*¬Ґвал Є®¬**¤*®© бва®ЄЁ}
  then{в®}
    begin
      read_file:=paramstr(1);{бзЁвлў*Ґ¬л© д*©« - ЇҐаўл© Ї*а*¬Ґва}
      search_value_string:=paramstr(2);
      val(search_value_string,search_value,k);
      write_file:=paramstr(3);
      result:=search(read_file,search_value);{бзЁвлў**ЁҐ Ё§ д*©«*, Ї®ЁбЄ}
      writing_to_file(write_file,result,begin_time);
    end
  else{Ґб«Ё *Ґв, в®}
    begin
      files_names_query(read_file,error,search_value);{§*Їа®б Ё¬Ґ*Ё д*©«®ў зҐаҐ§ Ї®«м§®ў*⥫мбЄЁ© Ё*Ґа䥩б}
      if (error='')
      then
        begin
          result:=search(read_file,search_value);{бзЁвлў**ЁҐ Ё§ д*©«*, Ї®ЁбЄ}
          writing(result,begin_time);
        end
      else
        begin
          writeln(error);
          writeln('Ќ*¦¬ЁвҐ Enter ¤«п Їа®¤®«¦Ґ*Ёп.');
          readln;
        end;
    end;
end.

function FoundByBinarySearch
(
LowIdx,
HighIdx : LongInt;
var   Result  : LongInt;
const GoalIs  : CompareFunc;
var   Data;
var   Goal
) : Boolean;
var
CompVal : CompareResults;
begin
FoundByBinarySearch := FALSE;
 
if HighIdx < LowIdx then
Exit;
 
Result := LowIdx + ((HighIdx-LowIdx) div 2);
CompVal := GoalIs(Result, Data, Goal);
 
if CompVal = BinEqual then
FoundByBinarySearch := TRUE
else if (LowIdx < HighIdx) then
begin
if CompVal = BinLess then
HighIdx := Result-1
else 
LowIdx  := Result+1;
FoundByBinarySearch := FoundByBinarySearch(
LowIdx, HighIdx, Result, GoalIs, Data, Goal)
end
else if (CompVal = BinLess) then
Dec(Result)
end;