程序中了给了一个可以重复利用的二维曲线绘制类CGraphics，并派生了线形曲线类模板、单对数曲线类模版、双对数曲线类模版。-Procedure to the repeat use of a two-dimensional curve drawing category CGraphics, and derived a linear curve of class template, a one-on-curve-type template, double logarithmic curve-typ