Compilare: user.cpp: In member function ‘bool cmp::operator()(const string&, const string&)’: user.cpp:14:24: warning: array subscript has type ‘char’ [-Wchar-subscripts] return poz[a[i]]<poz[b[i]]; ^ user.cpp:14:34: warning: array subscript has type ‘char’ [-Wchar-subscripts] return poz[a[i]]<poz[b[i]]; ^ user.cpp: In function ‘int main()’: user.cpp:37:19: warning: array subscript has type ‘char’ [-Wchar-subscripts] poz[cod[i]]=i; ^