Compilare: user.cpp: In function ‘bool cmp(std::string, std::string)’: user.cpp:10:36: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (a[i]!=b[i]) return ord[a[i]]<ord[b[i]]; ^ user.cpp:10:46: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (a[i]!=b[i]) return ord[a[i]]<ord[b[i]]; ^ user.cpp: In function ‘int main()’: user.cpp:39:39: warning: array subscript has type ‘char’ [-Wchar-subscripts] for (i=0; i<12; ++i) ord[s[i]]=i; ^