分段线性插值的C++代码实现，实现了基本的插值功能和方程拟合，可供初学者使用-Piecewise linear interpolation C++ code to achieve the basic functions and interpolation equation fitted for beginners to use

用于线性拟合的评判，光谱波长的选择及光谱波段的选择。(The judgment of linear fitting)