Compilare: user.cpp: In function ‘std::string greedy1(const string&)’: user.cpp:16:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < str.length(); j++) ^ user.cpp:18:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j + 1 < str.length() && str[j] != str[j+1]) ^ user.cpp: In function ‘std::string greedy2(const string&)’: user.cpp:37:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 1; j < str.length(); j++) ^