两个链接错误 一般 是什么引起的？
testmain.obj : error LNK2005: "class std::basic_ifstream <char,struct std::char_traits <char> > in " (?in@@3V?$basic_ifstream@DU?$char_traits@D@std@@@std@@A) already defined in newBookStorage.obj
Debug/classtest.exe : fatal error LNK1169: one or more multiply defined symbols found
[解决办法]
两个文件里定义了同名流对象
[解决办法]
extern *
