Hi! I have been posted content of ccna1 final exam (latest and only question.) I will post the answer and insert image on sunday. If you care, please subscribe your email an become a first person have full test content. Subcribe now Some question have not content because this question have images content. So that can you wait for me? SUNDAY 1. A user sees the command prompt: Router(config-if)# . What task can be performed at this mode? Reload the device. Perform basic tests. Configure individual interfaces. Configure individual terminal lines. 2. Refer to the exhibit. Host A attempts to establish a TCP/IP session with host C. During this attempt, a frame was captured with the source MAC address 0050.7320.D632 and the destination MAC address 0030.8517.44C4. The packet inside the captured frame has an IP source address 192.168.7.5, and the destination IP address is 192.168.219.24. At which point in the network was this packet captured? leaving host A leaving ATL leaving...
Well, what I usually do is have my methods that could error-out at runtime take a reference to a NSError pointer. If something does indeed go wrong in that method, I can populate the NSError reference with error data and return nil from the method.
ReplyDeleteExample:
- (id) endWorldHunger:(id)largeAmountsOfMonies error:(NSError**)error {
// begin feeding the world's children...
// it's all going well until....
if (ohNoImOutOfMonies) {
// sad, we can't solve world hunger, but we can let people know what went wrong!
// init dictionary to be used to populate error object
NSMutableDictionary* details = [NSMutableDictionary dictionary];
[details setValue:@"ran out of money" forKey:NSLocalizedDescriptionKey];
// populate the error object with the details
*error = [NSError errorWithDomain:@"world" code:200 userInfo:details];
// we couldn't feed the world's children...return nil..sniffle...sniffle
return nil;
}
// wohoo! We fed the world's children. The world is now in lots of debt. But who cares?
return YES;
}
We can then use the method like this. Don't even bother to inspect the error object unless the method returns nil:
// initialize NSError object
NSError* error = nil;
// try to feed the world
id yayOrNay = [self endWorldHunger:smallAmountsOfMonies error:&error];
if (!yayOrNay) {
// inspect error
NSLog(@"%@", [error localizedDescription]);
}
// otherwise the world has been fed. Wow, your code must rock.
We were able to access the error's localizedDescription because we set a value for NSLocalizedDescriptionKey.
The best place for more information is Apple's documentation. It really is good.
There is also a nice, simple tutorial on Cocoa Is My Girlfriend.
Great answer Alex. One potential issue is the NULL dereference. Apple's reference on Creating and Returning NSError objects
ReplyDelete...
[details setValue:@"ran out of money" forKey:NSLocalizedDescriptionKey];
if (error != NULL) {
// populate the error object with the details
*error = [NSError errorWithDomain:@"world" code:200 userInfo:details];
}
// we couldn't feed the world's children...return nil..sniffle...sniffle
return nil;
...
Please refer following tutorial
ReplyDeletei hope it will helpful for you but prior you have to read documentation of NSError