说明：  这段代码基本适合画各种坐标曲线，既可以把原点画在坐标轴上，也可以不画在坐标轴上。为了方便大家调试运行，我全部改成了VC代码，只要在VC中新建一个project，把下面的代码拷贝到OnDraw()函数中即可实现。各位只要稍微修改一下，就可以在其他各种编程语言中实现。
(The code for drawing all kinds of coordinates of the basic curve, we can draw in the axis origin, it may not draw in the axis. In order to facilitate debugging run, all of which I turned into a VC code, as long as the VC in a new project, copy the following code to the OnDraw () function can be realized. Just a little tinkering, you can in a variety of other programming languages to achieve.)