Compilare: user.cpp: In function ‘bool factor()’: user.cpp:88:20: warning: array subscript has type ‘char’ [-Wchar-subscripts] else val=v[s[p]]; ^ user.cpp: In function ‘int main()’: user.cpp:102:12: warning: array subscript has type ‘char’ [-Wchar-subscripts] v[x]=v[x]==0?1:0; ^ user.cpp:102:17: warning: array subscript has type ‘char’ [-Wchar-subscripts] v[x]=v[x]==0?1:0; ^