/in/foo.cc:4:15: error: 'string' was not declared in this scope
 int FindCount(string &s, string &t)
               ^~~~~~
/in/foo.cc:4:23: error: 's' was not declared in this scope
 int FindCount(string &s, string &t)
                       ^
/in/foo.cc:4:26: error: 'string' was not declared in this scope
 int FindCount(string &s, string &t)
                          ^~~~~~
/in/foo.cc:4:34: error: 't' was not declared in this scope
 int FindCount(string &s, string &t)
                                  ^
/in/foo.cc:4:35: error: expression list treated as compound expression in initializer [-fpermissive]
 int FindCount(string &s, string &t)
                                   ^