Compilare: user.c:3:1: warning: return type defaults to ‘int’ [enabled by default] main(){ ^ user.c: In function ‘main’: user.c:4:8: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("f.in","r",stdin);freopen("f.out","w",stdout); ^ user.c:4:34: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("f.in","r",stdin);freopen("f.out","w",stdout); ^ user.c:5:6: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&p); ^