program Primtester_3;

{ simple primtester between range for perfomance- and filehandling 
has a function and procedure, consts, globals and locals, locs = 59
shows sequence, selection and iteration (units are implicit)
to teach programming for beginners in maXbox!}

const
  FROM_RANGE = 1000;
  TO_RANGE = 5000;

//globals
var  
  mylist: TStringList;   //is an object from class TStringList! 
  beforeTime, afterTime: string;

function checkPrim(acti: integer): boolean;
var //locals
  j: integer;
  isprim: boolean;
begin
  isprim:= true;
  for j:= 2 to round(SQRT(acti)) do 
    if ((acti mod j) = 0) then begin
      isprim:= false
      break
    end;   
  result:= isprim;
end;


procedure TestPrimNumbers(Vfrom_range, Vto_range: integer);
var acti, count: integer;
begin
  count:= 0; //init
  mylist:= TStringList.create;
  for acti:= Vfrom_range to Vto_range do begin
    inc(acti)
    if checkPrim(acti) then begin
      inc(count)
      mylist.add(intToStr(count) +': '+intToStr(acti))
    end //if
  end //for
end;

//main program
begin
  //time performance
  beforeTime:= Now;
    TestPrimNumbers(FROM_RANGE, TO_RANGE);
  afterTime:= Now;
  writeln('start: '+ beforeTime + ' from: '+intToStr(FROM_RANGE))
  writeln('stop: ' + afterTime + ' to: '+intToStr(TO_RANGE))
  mylist.add(memo2.text)
  mylist.saveToFile('primetest8.txt')
  //memo2.lines.loadFromFile('primetest8.txt')     
  mylist.Free;
  //orthogonal and idempotent!
end.