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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
Posted by Luis Paulino
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
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
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
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"];