Compilare: user.c: In function ‘main’: user.c:61:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("vis.in","r",stdin); ^ user.c:62:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("vis.out","w",stdout); ^ user.c:63:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d%d%d%d",&n,&k1,&k2,&l1,&c1,&l2,&c2); ^ user.c:66:18: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i][j]); ^