Swift array declare

If you declare array like this.

var ar = [Int]()

Then add elements

ar[0]=1

ar[1]=2

When get values, it show you error, we must use append to add elements.

ar.append(1)

If you declare array like this.

var ar=[Int](count: 8, repeatedValue: 0)

Now array will have 8 elements with the same value 0.

If you add elements like this.

ar.append(1)

Now number 1 become the ninth elements, if get value from 1-8 it still show zero number.

To avoid this, we add element like this.

ar[0]=1

If you declare array like this.

var ar = NSMutableArray(capacity: 15)

Now we can’t use append, we must add elements like this

ar[0]=1

ar[1]=3