Compilare: user.cpp: In function ‘int main()’: user.cpp:52:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<sol.size(); ++i)printf("%.6f\n", sol[i]); ^ user.cpp:27:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.cpp:28:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("xmoto.in", "r", stdin); ^ user.cpp:29:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("xmoto.out", "w", stdout); ^ user.cpp:30:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%lf", &n, &l); ^ user.cpp:34:58: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%f%f%f%f%d", &e.a, &e.b, &e.k, &e.q, &e.v); ^