Compilare: main.c: In function 'main': main.c:18:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("cmmdc.in","r",stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:19:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("cmmdc.out","w",stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:21:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&a,&b); ^~~~~~~~~~~~~~~~~~~~