Compilare: user.c: In function ‘main’: user.c:21:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("drumuri3.in","r",stdin),freopen("drumuri3.out","w",stdout),scanf("%d%d%d%d",&n,&m,&k,&q),k--; ^ user.c:21:45: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("drumuri3.in","r",stdin),freopen("drumuri3.out","w",stdout),scanf("%d%d%d%d",&n,&m,&k,&q),k--; ^ user.c:21:78: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("drumuri3.in","r",stdin),freopen("drumuri3.out","w",stdout),scanf("%d%d%d%d",&n,&m,&k,&q),k--; ^ user.c:23:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&i,&j),a[i][j]=a[j][i]=1; ^ user.c:34:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&i,&j),printf("%d\n",b[i][j]); ^