Compilare: user.c: In function ‘main’: user.c:11:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("matrice.in","r",stdin),freopen("matrice.out","w",stdout),scanf("%d%d%d",&n,&m,&a); ^ user.c:11:44: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("matrice.in","r",stdin),freopen("matrice.out","w",stdout),scanf("%d%d%d",&n,&m,&a); ^ user.c:11:76: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("matrice.in","r",stdin),freopen("matrice.out","w",stdout),scanf("%d%d%d",&n,&m,&a); ^ user.c:13:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",r+i); ^ user.c:15:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",c+i); ^