Compilare: user.c: In function ‘main’: user.c:4:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("lacate.in","r",stdin),freopen("lacate.out","w",stdout),scanf("%d",&n),c=n-1,l=c*n/2,printf("%d %d\n",l,c),l=1; ^ user.c:4:40: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("lacate.in","r",stdin),freopen("lacate.out","w",stdout),scanf("%d",&n),c=n-1,l=c*n/2,printf("%d %d\n",l,c),l=1; ^ user.c:4:71: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("lacate.in","r",stdin),freopen("lacate.out","w",stdout),scanf("%d",&n),c=n-1,l=c*n/2,printf("%d %d\n",l,c),l=1; ^