Compilare: user.cpp: In function ‘int main()’: user.cpp:129:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < F.size(); i += 2) { ^ user.cpp:166:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < F.size(); i += 2) { ^ user.cpp:106:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nowhere-zero.in","r",stdin); ^ user.cpp:107:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nowhere-zero.out","w",stdout); ^ user.cpp:109:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:110:63: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i = 1; i <= n; i++) scanf("%lf%lf", &P[i].x, &P[i].y); ^ user.cpp:112:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &a, &b); ^