Compilare: user.cpp: In function ‘int main()’: user.cpp:14:12: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[v[dr]]++; ^ user.cpp:15:15: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(fr[v[dr]]==1) ^ user.cpp:19:19: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(fr[v[st]]>1) ^ user.cpp:21:14: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[v[st]]--; ^ user.cpp:24:13: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[v[st]]--; ^