uses crt, graph;
var a, b: integer;
    x0,y0,x1,y1: integer;
    alpha: integer;
begin
a:=9;b:=2;
initgraph(a,b,'c:\programme\tp\bgi');
x0:=300;y0:=300;x1:=300;y1:=300;

for alpha:=1 to 100 do begin
x1:=trunc(x0 * cos(alpha)) - trunc(x0 * sin(alpha));
y1:=trunc(x0 * sin(alpha)) + trunc(y0 * cos(alpha));
setcolor(yellow);
line(x0,y0,x1,y1);
delay(100);
if keypressed then halt;
end;

end.