Question

we are trying to add objects to an array , and when its full( capacity=10) , to shift all the values forward and erase the first (such as shift register)

i was trying to do the next and it allways crash after 10, because 9 beyond bounds of 8..??

if (count>9)
{

    for(count=0;count<9;count++)    
    {
            NSLog(@"%@",listOfEvents);
        [listOfEvents removeObjectAtIndex:count];
        [listOfEvents insertObject:[listOfEvents objectAtIndex:(count+1)] atIndex:count];

    }
    [listOfEvents removeObjectAtIndex:9];   
    [listOfEvents insertObject:event atIndex: 9];       
}


else
        [listOfEvents addObject:event];

count++;

when i have tried without removing object ,i get another error .
what am i doing wrong?
why cant i add values to some index, when there is a space index befor him? ?
thanks a lot .

Answer 1

You don’t actually have to do it this way, since NSArray will perform the “downsliding” of elements on its own:

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

(NSMutableArray)

So

if (count > 9) [array removeObjectAtIndex: 0];
[array addObject: newObject];

should be sufficient. NSMutableArray behaves more like an ArrayList in Java, or a List in C#, and less like a plain C array.