More often then not you need to talk about more than one variable, a collection of data. The most simple construct to do that is the array. The data is stored consecutively as a block. The array is also the list data-structure with the least overhead concerning the access and is the only list data-structure, which is supported without any libraries.

To access an member of the array you use the subscript operator []. In C arrays starts at index 0 and ends at index n-1, where n is the number of members.