Compilare: main.cpp: In function 'int main()': main.cpp:30:22: warning: array subscript has type 'char' [-Wchar-subscripts] while (num[cand] == 0) ^ main.cpp:33:18: warning: array subscript has type 'char' [-Wchar-subscripts] if (num[j]) { ^ main.cpp:34:36: warning: array subscript has type 'char' [-Wchar-subscripts] string s = ans, aux(num[j], j + 'a'); ^ main.cpp:41:17: warning: array subscript has type 'char' [-Wchar-subscripts] --num[cand]; ^