拉格朗插值算法实现。该例子用c++实现拉格朗日差值算法，代码已经进过测试，可直接运行-LaGrand interpolation algorithm. The example used c++ Lagrangian difference algorithm, the code has been to test, and can be run directly

用于拉格朗日插值法的计算方法，便于理解的(method for chu xue zhe shiyong ok ok ok ok ok)