Compilare: main.c: In function 'main': main.c:5:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("alee.in","r",stdin),freopen("alee.out","w",stdout),scanf("%d%d",&n,&m); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:5:34: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("alee.in","r",stdin),freopen("alee.out","w",stdout),scanf("%d%d",&n,&m); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:5:65: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] freopen("alee.in","r",stdin),freopen("alee.out","w",stdout),scanf("%d%d",&n,&m); ^~~~~~~~~~~~~~~~~~~ main.c:7:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&i,&k),a[i][k]=-1; ^~~~~~~~~~~~~~~~~~~ main.c:8:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&b,&d,&o,&q); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~