Compilare: user.cpp: In function ‘bool cmp(std::__cxx11::string, std::__cxx11::string)’: user.cpp:18:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < a.size() && a[i] == b[i]) ^ user.cpp: In function ‘bool isSubstring(std::__cxx11::string&, std::__cxx11::string&)’: user.cpp:74:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < a.size() && j < b.size()) ^ user.cpp:74:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < a.size() && j < b.size()) ^ user.cpp:76:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j < b.size() && a[i] != b[j]) ^ user.cpp:83:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] return b[j] == a[a.size() - 1] && i == a.size(); ^