Compilare: user.cpp: In function ‘bool fac(int)’: user.cpp:25:52: warning: array subscript has type ‘char’ [-Wchar-subscripts] else if (rs[p] >= 'A' && rs[p] <= 'Z') r = u[rs[p]], ++p; ^ user.cpp: In function ‘int main()’: user.cpp:48:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s .size(); i++) ^ user.cpp:57:32: warning: array subscript has type ‘char’ [-Wchar-subscripts] else rs[++cnt] = s[i], u[s[i]] = 0; ^ user.cpp:63:6: warning: array subscript has type ‘char’ [-Wchar-subscripts] u[c] = !u[c]; ^ user.cpp:63:14: warning: array subscript has type ‘char’ [-Wchar-subscripts] u[c] = !u[c]; ^ user.cpp: In function ‘bool fac(int)’: user.cpp:26:9: warning: ‘r’ may be used uninitialized in this function [-Wmaybe-uninitialized] return r; ^