读取文件：

( 1960 : 30 64 6 )
(1970 : 24 69 7 )
(1980 : 23 68 9 )
(1990 : 18 70 12)
(2000 : 15 68 17 )
(2010 : 13 64 23 )
(2020 : 12 60 28)
( 2030 : 11 59 30 )
( 2040 : 11 56 33 )
 

运行代码：

//绘制数据图
#include"std_lib_facilities.h"
#include"GUI/Simple_window.h"
#include"GUI/Graph.h"
#include"GUI/Point.h"
//------------------------------------------------------------------------
//定义保存数据项的Distribution类型
struct Distribution
{
	int year, young, middle, old;
};
//------------------------------------------------------------------------
//定义读取数据项的输入操作符
istream& operator>>(istream& is, Distribution& d)
{
	char ch1 = 0;
	char ch2 = 0;
	char ch3 = 0;
	Distribution dd;

	if (is >> ch1 >> dd.year
		>> ch2 >> dd.young >> dd.middle >> dd.old
		>> ch3)
	{
		if (ch1 != '(' || ch2 != ':' || ch3 != ')')
		{
			is.clear(ios_base::failbit);
			return is;
		}
	}
	else 
		return is;
	d = dd;
	return is;
}
//--------------------------------------------------------------------------
//定义比例缩放类
class Scale
{
	int cbase;
	int vbase;
	double scale;
public:
	Scale(int b, int vb, double s) :cbase(b), vbase(vb), scale(s) {}
	int operator()(int v)const { return cbase + (v - vbase) * scale; }
};
//---------------------------------------------------------------------------
int main()
try{
	//构造一些常量
	const int xmax = 600;
	const int ymax = 400;

	const int x_orig = xmax / 2;
	const int y_orig = ymax / 2;
	const Point orig(x_orig, y_orig);

	const int r_min = -10;
	const int r_max = 11;

	const int n_points = 3000;

	const int x_scale = 30;
	const int y_scale = 30;

	const int base_year = 1960;
	const int end_year = 2040;

	const int xoffset = 100;
	const int yoffset = 60;

	const int xspace = 40;
	const int yspace = 40;

	const int xlength = xmax - xoffset - xspace;
	const int ylength = ymax - yoffset - yspace;

	const double xscale = double(xlength) / (end_year - base_year);
	const double yscale = double(ylength) / 100;
	//-----------------------------------------------------------------------
    //构建窗口
	Simple_window win(Point(100, 100), xmax, ymax, "Aging Japan");
	//-----------------------------------------------------------------------
	//打开文件
	string file_name = "japanese-age-data.txt";
	ifstream ifs(file_name.c_str());
	if (!ifs)error("can't open ", file_name);
    //-----------------------------------------------------------------------
	//数据比例缩放
	Scale xs(xoffset, base_year, xscale);
	Scale ys(ymax - yoffset, 0, -yscale);
	//------------------------------------------------------------------------
	//构造坐标系
	Axis x(Axis::x, Point(xoffset, ymax - yoffset), xlength,
		(end_year - base_year) / 10,
		"year 1960 1970 1980 1990  "
		"2000   2010  2020  2030  2040");
	x.label.move(-100, 0);
	x.set_color(Color::black);

	Axis y(Axis::y, Point(xoffset, ymax - yoffset), ylength, 10, "% of population");
	y.set_color(Color::black);

	Line current_year(Point(xs(2008), ys(0)), Point(xs(2008), ys(100)));
	current_year.set_color(Color::black);

	current_year.set_style(Line_style::dash);
	//------------------------------------------------------------------------
	//读取文件数据
	Open_polyline children;
	Open_polyline adults;
	Open_polyline aged;

	Distribution d;
	while (ifs >> d)
	{
		if (d.year < base_year || end_year < d.year)
			error("year out of range");
		if (d.young + d.middle + d.old != 100)
			error("percentages don't add up");
		int x = xs(d.year);
		children.add(Point(x, ys(d.young)));
		adults.add(Point(x, ys(d.middle)));
		aged.add(Point(x, ys(d.old)));

	}
	//------------------------------------------------------------------------
	//为图形添加标签并设置颜色
	Text children_label(Point(10, children.point(0).y), "age 0-14");
	children.set_color(Color::red);
	children_label.set_color(Color::red);

	Text adults_label(Point(10, adults.point(0).y), "age 15-64");
	adults.set_color(Color::blue);
	adults_label.set_color(Color::blue);

	Text aged_label(Point(10, aged.point(0).y), "age 65+");
	aged.set_color(Color::dark_green);
	aged_label.set_color(Color::dark_green);
    //------------------------------------------------------------------------
	//将不同的Shape对象添加到Window对象中
	win.attach(children);
	win.attach(adults);
	win.attach(aged);

	win.attach(children_label);
	win.attach(adults_label);
	win.attach(aged_label);

	win.attach(x);
	win.attach(y);
	win.attach(current_year);
	//------------------------------------------------------------------------
	//启动GUI系统
	win.wait_for_button();
	//------------------------------------------------------------------------
}
catch (exception& e) {
	cerr << "error:" << e.what() << '\n';
	keep_window_open();
	return 1;
}
catch (...) {
	cerr << "Oops:unknown exception!\n";
	keep_window_open();
	return 2;
}
//------------------------------------------------------------------------------

运行结果：