/in/foo.cc: In function 'int weishu(std::__cxx11::string)':
/in/foo.cc:7:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<x.size();i++) if(x[i]=='.') break;
          ~^~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:27:8: warning: statement has no effect [-Wunused-value]
   for(i;;i++)
        ^
/in/foo.cc:38:8: warning: statement has no effect [-Wunused-value]
   for(i;;i++)
        ^
/in/foo.cc:14:7: warning: unused variable 'z' [-Wunused-variable]
  char z;
       ^