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("rfinv.in","r",stdin),freopen("rfinv.out","w",stdout),scanf("%d",&t); ^ user.c:4:42: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("rfinv.in","r",stdin),freopen("rfinv.out","w",stdout),scanf("%d",&t); ^ user.c:4:72: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("rfinv.in","r",stdin),freopen("rfinv.out","w",stdout),scanf("%d",&t); ^ user.c:6:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.c:8:18: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",a+i,b+i); ^ user.c:11:18: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&d[i][j]),c[i][j]=0; ^