货物进销管理系统：程序首先打开并读取Inventory.dat中记录的所有库存记录，然后读取
Transactions.dat，处理这个文件中包含的事务，记录发货记录到Shipping.dat，并记录错误信息到Errors.dat中。最后更新库存到另外一个文件NewInventory.dat中。(The purchase and sale management system for goods: the program first opens and reads all records stored in Inventory.dat, then reads.
Transactions.dat, process the transaction contained in this file, record the shipment records to Shipping.dat, and record the error information to Errors.dat. Finally, update inventory to another document, NewInventory.dat.)