Compilare: user.cpp: In function ‘int main()’: user.cpp:50:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v1.size(); ++ i) ^ user.cpp:51:57: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] cout << v1[i] << " \n"[i + 1 == v1.size()]; ^ user.cpp:53:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v2.size(); ++ i) ^ user.cpp:54:57: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] cout << v2[i] << " \n"[i + 1 == v2.size()]; ^