(* Takahashi's Plotting Assignment #2 *)
(* 980427 KUBO Takuya *)

Clear[f, flist, newpointlist];
$DefaultFont = {"Helvetica", 14};

f[x_] := r x (1 -x);
flist := NestList[f, x, 100];
xyset = 20;
newpointlist := Map[
		Point,
		Transpose[{Table[r, {xyset}],Take[flist, -xyset]}]
];

r = 2.5;
dr = 0.002;

pointlist = {PointSize[0.0005]};
nextstep = 1;

While[
	nextstep > 0,
	Do[
		x = 0.1;
		AppendTo[
			pointlist,
			newpointlist
		];
		r += dr,
		{step, 1, nextstep}
	];
	Print["Step number = ", nextstep, "\n"];
	Show[
		Graphics[pointlist],
		PlotRange -> {
			{2.4, 4.0},
			{0.0, 1.0}
		},
		Axes -> True,
		AxesOrigin -> {2.4, 0.0}
	];
	nextstep = Input["Step number ? (0:stop) = "];
];
(* 逐次的にステップ数を入力して計算を続けます *)