1. Data Structures
Arrays

2. Array Most commonly used data structure
Ordered array, in which the data is stored in ascending (or descending) key order. This arrangement makes possible a fast way of searching for a data item: the binary search.

3. Example
Attendance monitoring program for cricket team --- using Array.
Insert player at arrival
Search player
Delete player after departure
Imagine that each player has been issued a team shirt with the player’s number on the back.
To make things visually interesting, the shirts come in a variety of colors --- number and color stored in array
Create an applet viewer for it --- insert player and randomly choose color NO DUPLICATION

4. Insertion / Searching
Each button press in a Workshop applet corresponds to a step that an algorithm carries out. The more steps required, the longer the algorithm takes.
Insertion taking One step because no empty cell in array ---- sequence (assume not doing dup)
Searching will take more steps
Average is half of steps like N/2
Worst case scenario is N
The time an algorithm takes to execute is proportional to the number of steps, so searching takes much longer on the average (N/2 steps) than insertion (one step).

5. Deletion 2 step procedure
Search required item + Clear cell
Fill holes/empty cell
A deletion requires (assuming no duplicates are allowed) searching through an average of N/2 elements and then moving the remaining elements (an average of N/2 moves) to fill up the resulting hole. This is N steps in all.

6. Duplicate Issues Primary key cannot duplicate
Human error chance so check all data items before insertion.
Searching with duplicates
N moves required (whole array search)
Insertion with duplicates
N moves to search duplicates
1 step insertion
Deletion with duplicates
N moves to search and N/2 moves to shift cells
Average will be based on how many duplicates

7. Average moves for 3 operations
Create program for this example
Manage it with classes so that class can be used for some other purpose. E.g separate array insertion separately. Like store serial # of travelers cheque
Apply abstraction

8. Ordered Array
Useful when more searching
Linear Search
Binary Search

9. Example

10. Logarithms & Equation