/in/foo.cc:1:19: warning: extra tokens at end of #include directive
 #include <fstream>　　　
                   ^
/in/foo.cc:2:17: warning: extra tokens at end of #include directive
 #include <cmath>　　　
                 ^
/in/foo.cc:3:20: warning: extra tokens at end of #include directive
 #include <iostream>　　　
                    ^
/in/foo.cc:5:17: warning: extra tokens at end of #include directive
 #include<vector>　　　
                 ^
/in/foo.cc: In member function 'list& list::jiaoji(list&)':
/in/foo.cc:24:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<data.size();i++)
               ~^~~~~~~~~~~~
/in/foo.cc:25:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int j=0;j<l2.data.size();j++)
                ~^~~~~~~~~~~~~~~
/in/foo.cc:30:2: warning: no return statement in function returning non-void [-Wreturn-type]
  }
  ^
/in/foo.cc: In member function 'void list::output()':
/in/foo.cc:33:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<data.size();i++)
               ~^~~~~~~~~~~~