Regarding the difference in declaring NSArray and NSMutableArray class

Hi guys, I was wondering what was the difference between the declaration of NSArray and NSMutableArray class.

So lets say I declare a NSArray of numbers with literals

NSArray *numbers = @[@22,@44,@55,@66];

This works fine as a NSArray. However, if I were to put the same content in a NSMutableArray.....

NSMutableArray *numbers = @[@22,@44,@55,@66];

The array will still be printed out, but I get an error "imcompatable pointer types initializing 'NSMutableArray*'with and expression of type 'NSArray*'

if follow the format that the video explains which is similar to one of the ways arrays can be declared in C++/ or using the "alloc init" method....

NSMutableArray *numbers = [[NSMutableArray alloc] init];
numbers[0] = @33;
numbers[1] = @44;
numbers[2] = @55;
numbers[3] = @77;

It get printed out with zero errors. I understand that the "[[NSMutableArray alloc] init];" plays a part in this. That, plus the fact that mutable arrays can be edited. Which brings me to 2 points I need to ask:

1 - why does the NSMutableArray must be declared with "[[NSMutableArray alloc] init];", resulting in an error-less output?

2 - if i ignore the warnings and continue to declare a NSMutableArray as literals, what risks do I face further down if I had a program what has that line as part of its code?

Cheers

• mervin