Compilare: user.cpp: In function ‘int cmp(const string&, const string&)’: user.cpp:20:24: warning: array subscript has type ‘char’ [-Wchar-subscripts] if ( pos[ x[i] ] != pos[ y[i] ] ) ^ user.cpp:20:39: warning: array subscript has type ‘char’ [-Wchar-subscripts] if ( pos[ x[i] ] != pos[ y[i] ] ) ^ user.cpp:21:34: warning: array subscript has type ‘char’ [-Wchar-subscripts] return pos[ x[i] ] < pos[ y[i] ]; ^ user.cpp:21:48: warning: array subscript has type ‘char’ [-Wchar-subscripts] return pos[ x[i] ] < pos[ y[i] ]; ^