array

The index of a single dimensional array is the number of an element within the array. The element at that index can be accessed by following the array name with the index, enclosed in square brackets.

The index ranges from 0 to the length of the array minus 1.

So, in an array, arr, with a length of 5, arr[0] denotes the first element and arr[4] denotes the last element.

As arrays, once created, remain fixed in size the index remains the same when you are inputting (setting) an element within the array or outputting (getting) that element from the array.