Compilare: user.cpp: In function ‘int main()’: user.cpp:94:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("matrice2.in", "r", stdin); ^ user.cpp:95:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("matrice2.out", "w", stdout); ^ user.cpp:97:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &n, &q); ^ user.cpp:101:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &nodes [++ u].val); ^ user.cpp:113:71: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d%d", &a [i].x1, &a [i].y1, &a [i].x2, &a [i].y2); ^