inserts an item at and index shifting what is currently at that index and beyond to the right, returning the last element in the array
inserts an item at the specified index, shifting whatever was at that index and before to the left, returning the first element in the array
inserts an item at the specified index, shifting whatever was at that index and before to the left, returning the first element in the array
[a,b,c,d], e, 0 -> [e,b,c,d], a [a,b,c,d], e, 3 -> [b,c,d,e], a
Removes the item at the specified index, shifting all elements with a lower index to the right, and setting arr(0) = a
Removes the item at the specified index, shifting all elements with a higher index to the left, and setting arr(arr.size - 1) = a
shifts the array to the left, inserting a's at the end
shifts the array to the right, inserting a's at the start