Compilare: user.cpp: In function ‘int main()’: user.cpp:75:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<TotalConvexHull.size(); j++) ^ user.cpp:53:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("tri3.in", "r", stdin); ^ user.cpp:54:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("tri3.out", "w", stdout); ^ user.cpp:56:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d", &N, &M); ^ user.cpp:58:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d", &a[i].x, &a[i].y); ^ user.cpp:67:46: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d %d %d", &X1, &Y1, &X2, &Y2); ^