用单链表实现集合的交、并、差运算，提供共用户选择操作的交互界面，使用命令提示的方式提示用户输入集合1和集合2，然后让用户选择运算方式（交、并、差）等，-Achieved with a single set of cross-linked, and, poor operation, providing a total operation of the user interface options, the way using the command prompt prompts the user for a collection of sets 1 and 2, and then let the user to select operation mode (intersection, union and difference), etc. ,