{ program 4.9
 graphic representation of a function
 f(x) = exp(-x) * sin(2*pi*x) }

program graph1;
const d = 0.0625; {1/16, 16 lines for interval [x,x+1]}
      s = 32; {32 character widths for interval [y,y+1]}
      h = 34; {character position of x-axis}
      c = 6.28318; {2*pi}  lim = 32;
var x,y : real;  i,n : integer;
begin
   for i := 0 to lim do
      begin x := d*i; y := exp(-x)*sin(c*x);
      n := round(s*y) + h;
      repeat  write(' ');  n := n-1
      until n=0;
      writeln('*')
   end
end.