Tutorial 2 Abstract Data Types

1. Tutorial 2Abstract Data Types

2. Admin Stuffs • Some of you request to change tutorial class… • Transfer within my own classes (T3, T4, T5, T6) is fine. • Transfer between different tutors requires permission. • Ask Dr Tan Sun Teck’s permission for such changes. • Refrain from asking lab assignments to me • I am not supposed to help you with debugging or finding the algorithm etc… • Bidding system not working (yet)  • If this system is not good, I will be forced to change it…

3. Abstract Data Type (ADT) • Data Structure: • “Structure of Data”, structure makes life easier • Algorithm: • Step by step way to solve certain problem • Abstract Data Type • Data + Operations (Algorithms) to organize that data structure • Walls: We do not need to know the implementation details • Examples: Complex Number, Sphere, ColoredSphere:Sphere, List, etc. • Wait!! Contradictions?? • We are given so many implementation details here! Why bother with details? • In fact, we are going to do that throughout this module  • To give you a strong theoretical foundation… • Later on, you will just use these ADTs for your programming tasks

4. Implementing ADT in Java: Class • Java class is used to implement these ADT • This is the basic pattern of a class implementation: • public class C { // save as C.java private (instance) attributes… public (instance) attributes, constructor, methods…} • Sometimes we use “Interface” • interface C_interface { // signature of public methods are mentioned here desired interfaces…} • public class C implements C_interface { // a guarantee that we will implement the methods implementation must adhere the agreed interface, otherwise we have compile error} • In main method: • public static void main(String[] args) { C cInstance = new C();}

5. Object Oriented Programming • We learned these OOP concepts via these two questions: • Q1: Programming using agreed interfaces; Abstraction provided by ADTs; Implementing ADTs in Java. • Q2: Software re-use, A demonstration of “Integration” of (F1_2008); (F1_Driver, F1_Team, F1_Championship); and (F1_Race)

6. Student Presentation • T3 • N/A • N/A • N/A • T4 • N/A • N/A • N/A • T5 • Tan Yan Hao • Tan Yan Hao • Tan Yan Hao • T6 • Wong Shiang Ker • Nguyen Duy Hoang • Nguyen Duy Hoang  Better participation level is expected for tutorial 3 onwards!

7. Question 1 & 2 - F1 (1) The answer for these two questions are in the Java source codes!

8. Visit this Simulator (free) at Singtel Headquarter, Somerset

9. Question 1 & 2 - F1 (2) • Coded by your TA: • F1_2008.java • Coded by you: • Q1: • F1_Driver.java • F1_Team.java • F1_Championship.java • Q2: • F1_Race.java The bridge between the two: INTERFACE Airbus 380 Integration Problem: http://news.airwise.com/story/view/1169812254.html

10. Q3 – Compact Array • How to add? • Find first empty slot, insert it (bad).  O(n) • Maintain an index of first empty slot, insert there, add the index by 1 (good).  O(1) • How to add when full? • Create a new array, double the size, copy the entries to new array. • How to edit? • Search it from left to right, if found, replace the content. • As soon as you hit an empty slot, it means that the entry is not in the compact array. • How to delete? • Search it, delete the entry, shift everything on the right side of it to left by one! Tedious! • What are the potential issues with (b) and (d)? (see above)

11. That’s all for today • Next week, we will continue our lesson with Linked List. • Maybe a better data structure than “compact array”, especially for Q3. • Remember that the “best” data structure depends on the given scenario!