Leo Yun Tao15,955 Points
Why do I get an error when I put array[index -= 1] rather than array[index - 1]
Steven Parker186,477 Points
index -= 1 is an assignment which changes the value of
index but the expression itself does not provide a value to select an array element with.
On the other hand, the expression
index - 1 has a value that can be used to select an array element. And it provides a smaller value without changing the value of