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Luis Kentzler
13,869 PointsInvalid NSNumber declaration?
I'm stuck at this code challenge, and don't seem to know why. The challenge states:
Declare another variable named 'planck' of type NSNumber and assign it the value 6.626.
My approach to this is:
NSNumber *planck = [NSNumber numberWithFloat:6.626];
I think this declares the variable planck and initializes it with a float value of 6.626. Why isn't this working?
Also, could someone explain me the difference of initializing NSNumber in the 3 different ways the video shows?:
NSNumber *planck; planck=[[NSNumber alloc] initWithFloat:6,626];
NSNumber *planck = @6.626;
NSNumber *planck = [NSNumber numberWithFloat:6.626];
Thanks a lot guys!
2 Answers
Amit Bijlani
Treehouse Guest TeacherYour answer is right but our CC engine is a bit restrictive so the only answer that works is: NSNumber *planck = @6.626;. All valid ways of declaring a float and they all result in the same instance variable. Neither has a benefit over the other. However, the number literal (using the @ symbol) is latest addition to Objective-C and the preferred way of creating a number.
Dave Ko
11,915 PointsNSNumber *planck = [NSNumber numberWithDouble:6.626];
Give this a try for planck