超市收银，添加货物，动态修改货物信息，文件操作，读取，更新，修改-Supermarket cash register, add cargo, cargo information dynamically modified, file operations, read, update, modify,

闲暇之余利用C语言做的一个关于模拟超市收银过程的一个小程序-In her spare time use of C language to do a simulation of the process of supermarket cash register of a small program