Compilare: user.cpp: In function ‘bool get_or(std::string)’: user.cpp:52:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<s.size() && s[i]=='|') ^ user.cpp: In function ‘bool get_xor(std::string)’: user.cpp:62:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<s.size() && s[i]=='^') ^ user.cpp: In function ‘bool eval(std::string)’: user.cpp:72:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<s.size() && s[i]=='&') ^ user.cpp: In function ‘int main()’: user.cpp:88:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s1.size();++i) ^ user.cpp:90:45: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(isalpha(s1[i]) && !fol1[s1[i]]) ^ user.cpp:94:27: warning: array subscript has type ‘char’ [-Wchar-subscripts] fol1[s1[i]]=1; ^ user.cpp:97:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s2.size();++i){ ^ user.cpp:98:45: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(isalpha(s2[i]) && !fol2[s2[i]] && !fol1[s2[i]]) ^ user.cpp:98:61: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(isalpha(s2[i]) && !fol2[s2[i]] && !fol1[s2[i]]) ^ user.cpp:102:27: warning: array subscript has type ‘char’ [-Wchar-subscripts] fol2[s2[i]]=1; ^ user.cpp:104:50: warning: array subscript has type ‘char’ [-Wchar-subscripts] else if(isalpha(s2[i]) && !fol2[s2[i]]) ^ user.cpp:105:31: warning: array subscript has type ‘char’ [-Wchar-subscripts] {cnt2++;fol2[s2[i]]=1;} ^