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

Luis Paulino
PLUS
Luis Paulino
Courses Plus Student 1,779 Points

Hello, How am I writing the code wrong?

I don't know what I'm missing. What do I need to put in?

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

1 Answer

David Lin
David Lin
35,864 Points

NSString isn't initialized with objects and keys, just init:

NSMutableDictionary *carDict = [[NSMutableDictionary alloc]initWithObjectsAndKeys: @"Honda", @"Make", @"Accord", @"Model", nil];
NSString *myRide= [[NSString alloc] init];
Luis Paulino
Luis Paulino
Courses Plus Student 1,779 Points

Oh, thank you for clearing that up for me. Can, I ask why?.

David Lin
David Lin
35,864 Points

Luis, You're welcome. It is because NSString's initializer is set up that way, since it only needs a single value, not a key-value pair like NSDictionary (and NSMutableDictionary). You can also init the dictionaries in the same way, and then append key-value pairs to it later. For example,

NSMutableDictionary *dictionary = [[NSMutableDictionary alloc] init];
[dictionary setValue:@"value" forKey:@"key"];