program N_tougao;
uses crt,graph;
const b=10;
var driver,mode,n,i:integer;
    x,y,xc,yc,r:real;
begin
  ClrScr;
  write(' Unesite broj temena (n):');
  readln(n);
  write(' Unesite poluprecnik opisane kruznice (r) :');
  readln(r);
  r:=r*b;
  driver:=detect;
  InitGraph(driver,mode,'');
  if (r>0) and (r<((GetMaxX+1) div 2)) and (n>2)
    then
    begin
      xc:=GetMaxX div 2;
      yc:=GetMaxY div 2;
      setbkcolor(white);
      setcolor(magenta);
      MoveTo(round(xc+r),round(yc));
      for i:=1 to n do
      begin
        x:=xc+r*cos(2*pi/n*i);
        y:=yc+r*sin(2*pi/n*i);
        LineTo(round(x),round(y));
      end;
    SetFillStyle(1,magenta);
    FloodFill(GetMaxX div 2,GetMaxY div 2,magenta);
    readln;
    closegraph
  end
  else
  begin
    restorecrtmode;
    writeln(' Objekat nije vidljiv! Poluprecnik mora biti u intervalu [0,',GetMaxY div 2,'], a broj tjemena veci od 2!');
    readln
  end
end.