Compilare: main.c: In function 'main': main.c:5:2: 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; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:5:33: 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; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:5:66: 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; ^~~~~~~~~~~~~~