What is an index?
Each element in the array has a subscript or index that differentiates it from every other element in the array.
(Some people call it a subscript while others call it an index.)
The index is positive integer that indicates the position of a particular element relative to the first element in the array.
The first element in the array always has an index value of 0.
We access the data value we are searching for in an array by its subscript or index.