运行代码:

//函数图形化显示练习（进阶）
#include"std_lib_facilities.h"
#include"GUI/Simple_window.h"
#include"GUI/GUI.h"
#include"GUI/Graph.h"
#include"GUI/Point.h"
//定义函数
double one(double) { return 1; }

double slope(double x) { return x / 2; }

double square(double x) { return x * x; }

double sloping_cos(double x) { return slope(x) + cos(x); }
//-----------------------------------------------------------------------------
int main()
try
{
	//定义常量
	int xmax = 600;
	int ymax = 600;//窗口尺寸

	int xlength = 400;
	int ylength = 400;//坐标轴长度

	int x_scale = 20;
	int y_scale = 20;//坐标轴缩放比例

	Point orig(300, 300);//坐标轴原点

	int r_min = -10;
	int r_max = 11;//自变量范围

	int n_points = 400;//显示的函数值数量
	//--------------------------------------------------------------------------
	//建立窗口
	Simple_window win(Point(100, 100), xmax, ymax, "Function graphs");
	//--------------------------------------------------------------------------
	//建立坐标轴
	Axis x(Axis::x, Point(100, 300), xlength,x_scale, "1==20 pixels");
	x.set_color(Color::red);

	Axis y(Axis::y, Point(300, 500), ylength, y_scale, "1==20 pixels");
	y.set_color(Color::red);

	win.attach(x);
	win.attach(y);
    //---------------------------------------------------------------------------
	//构造函数
	Function f1(one, r_min, r_max, orig, n_points, 1, 1);
	f1.set_color(Color::black);
	win.attach(f1);
	
	Function f2(slope, r_min, r_max, orig, n_points, x_scale, y_scale);
	f2.set_color(Color::black);
	win.attach(f2);

	Function f3(square, r_min, r_max, orig, n_points, x_scale, y_scale);
	f3.set_color(Color::black);
	win.attach(f3);

	Function f4(cos, r_min, r_max, orig, n_points, x_scale, y_scale);
	f4.set_color(Color::blue);
	win.attach(f4);

	Function f5(sloping_cos, r_min, r_max, orig, n_points, x_scale, y_scale);
	f5.set_color(Color::black);
	win.attach(f5);
	//----------------------------------------------------------------------------
	//为函数添加标签
	Text t1(Point(100, 420), "x/2");
	t1.set_color(Color::black);
	win.attach(t1);
	//-----------------------------------------------------------------------------
	//启动GUI
	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: