Compilare: user.cpp: In function ‘int main()’: user.cpp:16:15: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[v[i]]++; ^ user.cpp:17:18: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(f[v[i]] == 1) ^ user.cpp:20:19: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[v[p]]--; ^ user.cpp:21:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(f[v[p]] == 0) ^