Compilare: main.c: In function 'main': main.c:46:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("zero.in","r",stdin),freopen("zero.out","w",stdout),scanf("%d%d%d%d",&l,&b,&p,&q); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:46:34: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("zero.in","r",stdin),freopen("zero.out","w",stdout),scanf("%d%d%d%d",&l,&b,&p,&q); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:46:65: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] freopen("zero.in","r",stdin),freopen("zero.out","w",stdout),scanf("%d%d%d%d",&l,&b,&p,&q); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~