/in/foo.cc: In function 'int main()':
/in/foo.cc:21:8: warning: statement has no effect [-Wunused-value]
  for(it;it!=str.end();it++)
        ^
/in/foo.cc:42:11: warning: statement has no effect [-Wunused-value]
     for(it;it!=str.end();it++)
           ^