/in/foo.cc:8:1: error: declaration does not declare anything [-fpermissive]
 string ;
 ^~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:17:21: error: 'ch' was not declared in this scope
         getline(cin,ch);
                     ^~
/in/foo.cc:18:15: error: 's' was not declared in this scope
         int l=s.size();
               ^