1. Constructing Objects Lab

2. Log into Wiley Plus

3. Read the problem Write a BankAccountTester class whose main method constructs a bank account, deposits $1,000, withdraws $500, withdraws another $400, and then prints the remaining balance. Also print the expected result. Your tester class should be called BankAccountTester. Use the following class in your solution: [Wplus gives you the BankAccount class code here]

4. Now You probably feel overwhelmed. You think: What do I do next? You react: Somebody tell me what to do. Professor reaction: take a deep breath, clear your mind and remember…..

5. ….what Eric Berlow said: “Hone in on the sphere of influence that matters most.” http://www.ted.com/talks/eric_berlow_how_complexity_leads_to_simplicity.html

6. What matters most? There are 2 classes Write a BankAccountTester class whose main method constructs a bank account, deposits $1,000, withdraws $500, withdraws another $400, and then prints the remaining balance. Also print the expected result. Your tester class should be called BankAccountTester. Use the following class in your solution: [Wplus gives you the BankAccount class code here]

7. What matters about the BankAccountTester? You have to write it and BankAccountTester has a main method that constructs a BankAccount and then invokes the methods of the Bank Account and then prints the results. Write a BankAccountTester class whose main method constructs a bank account, deposits $1,000, withdraws $500, withdraws another $400, and then prints the remaining balance. Also print the expected result. Your tester class should be called BankAccountTester. Use the following class in your solution: [Wplus gives you the BankAccount class code here]

8. What matters about the BankAccount class? It is already written for you. You need to understand its structure {You gotta know what is in it.} How do we understand class structures? – Make a UML Class Diagram

9. Writing a UML Class Diagram to reverse engineer code: Remember the 3 parts of Object Anatomy: name, attributes, methods What is the name of the class?

10. Name in a Class Diagram

11. What are the Attributes?

12. What are the methods

13. Where is the constructor and are there any overloads?

14. Where does the constructor go in the class diagram? A constructor is a method that is called when you create a NEW object; the scope is “classifier” instead of “instance”

15. To add parameters: Click on Properties with the desired constructor highlighted

16. Go to Parameters and add the name of the parameter, the datatype and kind

17. Class diagram completed

18. Remember there are 2 classes The BankAccount and the BankAccountTester

19. What does the BankAccountTester class look like? What do the words in the problem tell us? “Write a BankAccountTester class whose main method” We know the name of the class and a method name

20. Now ask yourself… How do these 2 classes interact? What type of diagram will help me understand how they interact? – Sequence Diagram

21. Put in the object lifelines for each of the objects; there is no instance name for the tester

22. Why isn't there a instance name for the Tester? Because a tester class is a class with a main method that contains statements to run methods of another class It is the class that makes the calls to the instance of classes [objects] It will occupy space in memory when running but we will not create NEW The main method kicks off the program

23. Just like a carburetor cant run all by itself and must live in a car to work; a class needs to live in a program Tester class Instance of a class AKA an object

24. Back to the problem: what is the first thing the tester does? Write a BankAccountTester class whose main method constructs a bank account, deposits $1,000, withdraws $500, withdraws another $400, and then prints the remaining balance. Also print the expected result.

25. What is the second thing the tester does? Write a BankAccountTester class whose main method constructs a bank account, deposits $1,000, withdraws $500, withdraws another $400, and then prints the remaining balance. Also print the expected result.

26. What is the third thing the tester does? Write a BankAccountTester class whose main method constructs a bank account, deposits $1,000, withdraws $500, withdraws another $400, and then prints the remaining balance. Also print the expected result.

27. What is the fourth thing the tester does? Write a BankAccountTester class whose main method constructs a bank account, deposits $1,000, withdraws $500, withdraws another $400, and then prints the remaining balance. Also print the expected result.

28. What is the Fifth thing the tester does? Write a BankAccountTester class whose main method constructs a bank account, deposits $1,000, withdraws $500, withdraws another $400, and then prints the remaining balance. Also print the expected result. Question: is there a dependent operation that must be performed to print the balance? Answer: yes, you have to get the balance before you can print it.

29. Fifth: Get the balance

30. And print it

31. What is the sixth thing the tester does? Write a BankAccountTester class whose main method constructs a bank account, deposits $1,000, withdraws $500, withdraws another $400, and then prints the remaining balance. Also print the expected result.

32. Now you have a picture of the program and it is time to code.

33. Launch LabRat and make the file BankAccountTester.java

34. Construct a new bank account object

35. Make a deposit [if you don’t remember how to invoke a method go back to object anatomy and look at the method ppt again]

36. Withdraw

37. withdraw

38. Get balance and assign to a variable if you don’t remember how to declare and add value to a variable go back and look at the API lecture

39. Print balance

40. Print expected result

41. Now submit to LabRat and see what happens.