/in/foo.cc: In function 'std::__cxx11::string getSwapped(std::__cxx11::string)':
/in/foo.cc:6:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < a.size() / 2; ++i){
                 ~~^~~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:34:3: error: return-statement with no value, in function returning 'int' [-fpermissive]
   return;
   ^~~~~~
/in/foo.cc:47:3: error: return-statement with no value, in function returning 'int' [-fpermissive]
   return;
   ^~~~~~
/in/foo.cc:51:2: error: return-statement with no value, in function returning 'int' [-fpermissive]
  return;
  ^~~~~~