Compilare: user.cpp: In function ‘void sortaret()’: user.cpp:23:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<vt[k].size(); ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:42:14: warning: array subscript has type ‘char’ [-Wchar-subscripts] E[ch1]=1; E[ch2]=1; ^ user.cpp:42:24: warning: array subscript has type ‘char’ [-Wchar-subscripts] E[ch1]=1; E[ch2]=1; ^ user.cpp:44:14: warning: array subscript has type ‘char’ [-Wchar-subscripts] v[ch1].push_back(ch2); ++grad[ch1]; ^ user.cpp:44:42: warning: array subscript has type ‘char’ [-Wchar-subscripts] v[ch1].push_back(ch2); ++grad[ch1]; ^ user.cpp:45:15: warning: array subscript has type ‘char’ [-Wchar-subscripts] vt[ch2].push_back(ch1); ^ user.cpp:60:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0; j<v[S].size(); ++j) { ^