A common way to group data is to have them in a list. In most cases the data is of the same type .

In computer a list is typically implemented as an array or pointer-based linked list.

Fig 4.1(p 50)

Operations on a list include:

1. Insertion : ( front + back + condition )

2. Deletion :  (  front + back + search key )

3. Traversal : visit each element and perform an operation on it such as print or update.

Note: Conditional insertion does not necessarily mean sorted insertion.