Compilare: user.cpp: In function ‘int main()’: user.cpp:34:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (x*x + x >= N && x*x != N) ^ user.cpp:34:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (x*x + x >= N && x*x != N) ^ user.cpp:36:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (x*x + x<N) ^