Compilare: user.c: In function ‘main’: user.c:4:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("z.in","r",stdin),freopen("z.out","w",stdout),a[1][1]=1,a[1][2]=2,a[2][1]=3,a[2][2]=4,scanf("%d%d",&n,&k); ^ user.c:4:38: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("z.in","r",stdin),freopen("z.out","w",stdout),a[1][1]=1,a[1][2]=2,a[2][1]=3,a[2][2]=4,scanf("%d%d",&n,&k); ^ user.c:4:104: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("z.in","r",stdin),freopen("z.out","w",stdout),a[1][1]=1,a[1][2]=2,a[2][1]=3,a[2][2]=4,scanf("%d%d",&n,&k); ^ user.c:6:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&l,&c),j=t=(1<<n),r=0; ^