数据库管理系统（Data Base Management System DBMS)是一种特殊的应

● A （75） infected computer may lose its data. （75）A. file B. data base C. virus D. progra

● A （75） infected computer may lose its data. （75）A． file B． data base C． virus D． program

● A （75） infected computer may lose its data. （75）A. file B. data base C. virus D. program

● A （75） infected computer may lose its data. （75）A. file B. data base C. virus D. program

关于数据库管理系统 （Data Base Management System DBMS) 下列说

有如下程序： class Base{ public: int data; }; class Derived1:public Base{}; class Derived2: