Compilare: main.c: In function 'main': main.c:5:3: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] { freopen("crescator2.in","r",stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:6:3: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("crescator2.out","w",stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:8:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&N); ^~~~~~~~~~~~~~