加密算法中经典的DES算法的C语言实现，利用此算法可以掌握对称加密算法的大致流程-Encryption algorithms, classic DES algorithm in C language, the use of this algorithm can grasp the general process of the symmetric encryption algorithm

C实现插值，二维插值，找了很久的东西，分享一下。-C implementation interpolation, two-dimensional interpolation, looking for something for a long time