Compilare: user.cpp: In function ‘int main()’: user.cpp:27:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=x=0;i<a.size();++i) ^ user.cpp:28:32: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(!T[x].Son[D[a[i]]]) ^ user.cpp:30:32: warning: array subscript has type ‘char’ [-Wchar-subscripts] T[x].Son[D[a[i]]]=++k; ^ user.cpp:33:35: warning: array subscript has type ‘char’ [-Wchar-subscripts] else x=T[x].Son[D[a[i]]]; ^ user.cpp:36:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<S.size();++i) ^ user.cpp:39:32: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(!T[x].Son[D[S[j]]]) break; ^ user.cpp:40:30: warning: array subscript has type ‘char’ [-Wchar-subscripts] x=T[x].Son[D[S[j]]]; ^