Compilare: user.cpp: In function ‘void Prefix()’: user.cpp:14:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 2, K = 0; i < a.length(); i++) ^ user.cpp: In function ‘void KMP()’: user.cpp:27:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1, K = 0; i < b.length(); i++) ^ user.cpp:34:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (K == a.length() - 1) ^