NSKeyedArchiver:对象序列化,将对象保存在文件里
NSKeyedUnarchiver:反序列化
#if ARCHIVE
// create and archive a roster
Roster *roster = [[Roster alloc] init];
[roster create];
[NSKeyedArchiver archiveRootObject:roster toFile:fileName];
[roster release];
#endif
#if UNARCHIVE
// unarchive roster
Roster *unarchive = [NSKeyedUnarchiver unarchiveObjectWithFile:fileName];
[unarchive print];
for (Athlete *athlete in [unarchive athletes])
[athlete print];
[unarchive release];
#endif
[pool release];
return 0;