Compilare: user.c: In function ‘main’: user.c:55:5: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("domino.in", "r", stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ user.c:56:5: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("domino.out", "w", stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ user.c:58:5: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &m); ^~~~~~~~~~~~~~~ user.c:61:9: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &u, &v); ^~~~~~~~~~~~~~~~~~~~~~