中文说明：简单的M文件、连续系统、离散系统、混合系统、变步长s-fuction；C语言编写s-fuction，回调函数、进程界面、数据层面、采样时间、工作向量、错误处理、过零检测s-fuction范例、时变连续传递函数的s-fuction范例、
English Description：
Simple m-file, continuous systems, discrete systems, hybrid systems, variable-step s-fuction;C language s-fuction, callback functions, processes, interfaces, data layer, vector, error handling, sampling time and work, continuous time-varying transfer function zero-crossing detection s-fuction example s-fuction example,