Compilare: user.cpp: In function ‘int main()’: user.cpp:19:54: warning: array subscript has type ‘char’ [-Wchar-subscripts] for (int i = 1; i <= n; i++) cin >> a[i], nr[a[i]]++; ^ user.cpp:21:16: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (!viz[a[i]]) ^ user.cpp:22:36: warning: array subscript has type ‘char’ [-Wchar-subscripts] while (a[i] <= st[v] && nr[st[v]]) viz[st[v]] = 0, v--; ^ user.cpp:22:48: warning: array subscript has type ‘char’ [-Wchar-subscripts] while (a[i] <= st[v] && nr[st[v]]) viz[st[v]] = 0, v--; ^ user.cpp:23:16: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (!viz[a[i]]) st[++v] = a[i], viz[a[i]] = 1; ^ user.cpp:23:43: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (!viz[a[i]]) st[++v] = a[i], viz[a[i]] = 1; ^ user.cpp:24:10: warning: array subscript has type ‘char’ [-Wchar-subscripts] nr[a[i]]--; ^