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iOS Object-Oriented Objective-C Memory, Arrays and Loops, Oh My! Alloc and Init

Posted by Marco Garduño
Marco Garduño
1,549 Points

whats wrong?

what am i missing???

variable_assignment.mm 
NSMutableDictionary*carDict=[[NSDictionary alloc] initWithObjectsAndKeys:"Make":"Honda","Model":"Accord" , nil];

3 Answers

Sam Chaudry
Sam Chaudry
25,519 Points
Sam Chaudry
Sam Chaudry
25,519 Points

Hi Marco you've got an incompatible pointer type you've declared NSDicitonary and pointed it to a NSMutableDictionary so thats where you've gone wrong. Try the solution below that will get you through the code challenge.

NSMutableDictionary * carDict = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"Accord",@"Model",@"Honda",@"Make", nil];

ARMANDO RODRIGUEZ
ARMANDO RODRIGUEZ
4,216 Points
ARMANDO RODRIGUEZ
ARMANDO RODRIGUEZ
4,216 Points

No this thing is broken.
I've tried both ways of initializing an NSMutableDictionary in one line and both fail the code check. 

NSMutableDictionary *carDict = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"Make", @"Honda", @"Model", @"Accord", nil];

This one fails. 

NSMutableDictionary *carDict = [[NSMutableDictionary alloc] initWithObjectsAndKeys:@"Make", @"Honda", @"Model", @"Accord", nil];

This one fails too. Those are the ONLY ways to do it in one line.
The only way to do it other than that is two lines...

NSMutableDictionary *carDict = [NSMutableDictionary alloc];
[carDict initWithObjectsAndKeys:@"Make",@"Honda",@"Model",@"Accord",nil];

There's something wrong with the test.

Shannon Gold
Shannon Gold
4,426 Points
Shannon Gold
Shannon Gold
4,426 Points

I tried answering the test like this because it's similar syntax to the sample in the previous video. However, I'm also getting a syntax error.

NSMutableDictionary *carDict = [[NSMutableDictionary alloc] initWithObjectsAndKeys: @"Make", @"Honda", @"Model", @"Accord", nil];

Then, I dug deeper and found this which works.

NSMutableDictionary *carDict = [[NSMutableDictionary alloc] initWithObjects:[NSArray arrayWithObjects:@"Honda", @"Accord", nil] forKeys:[NSArray arrayWithObjects:@"Make", @"Model", nil]];