Compilare: user.cpp: In function ‘int main()’: user.cpp:14:13: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[s[dr]]++; ^ user.cpp:15:16: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(fr[s[dr]]==1) ^ user.cpp:21:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(fr[s[st]]>1) ^ user.cpp:23:21: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[s[st]]--; ^ user.cpp:26:17: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[s[st]]--;st++;nr--; ^