NSMutableArray removeObjectAtIndex

Question

If I have an NSMutableArray with 10 objects

I run this line of code

[tempArray removeObjectAtIndex:0];

then

[tempArray count] should return 9

but does the entire Array shift up

Object At Index 1 moves to Index 0
Object at Index 2 moves to Index 1
...
Object at Index 9 moves to Index 8

or is Index 0 = nil?

Answer 1

From the NSMutableArray documentation :

To fill the gap, all elements beyond index are moved by subtracting 1 from their index.

Answer 2

The array will shift all of the objects down 1 from the right of the removed index. Index 0 will be what was at index 1 and so forth.

Answer 3

removeObjectAtIndex shifts indexes down

insertObjectAtIndex shifts indexed up

addObject adds object at the end so there is no shifting