Compilare: main.c: In function 'main': main.c:9:2: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("perm2.in","r",stdin),freopen("perm2.out","w",stdout),scanf("%d",&n); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:9:32: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("perm2.in","r",stdin),freopen("perm2.out","w",stdout),scanf("%d",&n); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:9:64: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] freopen("perm2.in","r",stdin),freopen("perm2.out","w",stdout),scanf("%d",&n); ^~~~~~~~~~~~~~ main.c:11:8: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",p+i),y[i]=p[i]; ^~~~~~~~~~~~~~~