--------------------Configuration: exam11 - Win32 Debug-------------------- Linking... exam12.obj : error LNK2005: _main already defined in exam11.obj Debug/exam11.exe : fatal error LNK1169: one or more multiply defined symbols found Error executing link.exe.

exam11.exe - 2 error(s), 0 warning(s) 程序本身是对的， 每次遇到这种问题的时候 关了vc后重新进入就可以运行了。