/in/foo.cc: In function 'int main()':
/in/foo.cc:10:3: error: 'fin' was not declared in this scope
   fin >> m_sum >> n;
   ^~~
/in/foo.cc:19:31: error: 'memset' was not declared in this scope
   memset(v_max,0,sizeof(v_max));
                               ^
/in/foo.cc:36:3: error: 'fout' was not declared in this scope
   fout << v_max[m_sum]*10 << endl;
   ^~~~