Compilare: user.cpp: In function ‘void fix_failure()’: user.cpp:52:61: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < (now ->failure ->index).size(); i ++){ ^ user.cpp: In function ‘void search()’: user.cpp:84:51: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 0; k < (now ->index).size(); k ++){ ^ user.cpp:85:40: warning: array subscript has type ‘char’ [-Wchar-subscripts] ++ ord[(now ->index)[k]]; ^