CSC 175 - Intermediate Programming

Dr. D. Chays

• Slides for CSC 171
• Examples for CSC 171
• Labs for CSC 171
• Clock24.java
• Slides for Chapter 1: Review of Java Fundamentals or you may prefer these slides for review: Review Part I and Review Part II
• Slides for Chapter 2: Principles of Programming and Software Engineering. This corresponds to chapter 1 of previous edition.
• 1/23: Driver (or main) and Blueprint (or data) classes in groups of 2, based on a theme of your choice.
• Review (CSC 171) Exercises on parameter passing:
  • Parameter Passing Tracing Exercise
  • Parameter Passing Coding Exercise
• 1/31 Exercise: JUnit exercise: MoneyTest, Money
• 2/5 Exercise: Complete the MoneyTest/Money exercises from last time; if you finished, here is the next exercise that builds on it: JUnit exercise: AccountTest, Account
• 2/14 example: PalindromeTest.java tests Palindrome.java
• 2/14 example: RollingDice is a Driver/main class that uses Dice which stores a collection of Die objects.
• Another example of an array of objects (SongCollection is a collection of Songs):
  • Tunes.java is a driver class which uses SongCollection.java which uses Song.java
• 2/14: Consider that a Bank has a collection of accounts. Exercise: using array of objects: BankTest, Bank. You may refer to the SongCollection example above; SongCollection is an ADT which, like Bank, has an array of objects.

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• Slides for Chapter 3: Recursion: The Mirrors. This corresponds to chapter 2 of previous edition.
• 2/21 Exercises:
  • a) Write JUnit tests for the iterative factorial method , including tests that violate the precondition.
  • b) Use the debugger to step through the iterative factorial method.
  • c) Make this method more fail-safe (by having it check its precondition and return an error code if the precondition was violated)
  • d) Review the documentation of your bank-related classes, according to the guidelines we discussed, i.e. what comments to include for each method (let me know if any question). Generate documentation webpages (like those in the Java Standard Library) for your javadoc-commented bank-related classes; in BlueJ this means clicking on Tools...Project Documentation.
  • e) Fail-safe programming exercise:
    • 2/21: Read and understand: IncomeStatistics.java
    • 2/21: Define the readData() method according to the given documentation: IncomeStatisticsV2.java
• 2/28 Exercise: Are there any privacy leaks (as discussed in 2/28 lecture) in your Account and Bank classes? Write JUnit tests to expose these faults and then fix by replacing assignment statements involving (non-String) objects, that create aliases (which can lead to unwanted side effects), with calls to a copy constructor. The assignments needing modification may be explicit (object1 = object2;) or implicit (return this.object;).
  • Any privacy leaks in your Money class, if it is immutable?
  • Any privacy leaks in your Bank's methods, e.g. addAccount, search...?
• 3/5 Intro to abstract methods (and classes), inheritance and polymorphism:
  Download the example demo'd in lecture; extract the files using 7zip and open the project; this version has some errors which we will try to understand and fix:
  • Look at the Rectangle class; why does it compile even though its area method is missing (i.e. commented out) ? Don't fix it yet.
  • Uncomment the header of the area method in the Shape class. Recompile the abstract class Shape. Try to compile the Rectangle class; now the compiler gives us some useful information, but what does it mean? How to fix it?
  • Add the @Override annotation appropriately above the method header of area method in Rectangle and Circle. What is the purpose of this, and when should you use the annotation?
  • Override the toString method in Rectangle and Circle.
  • Read, understand and run the main method of PolymorphismDemo; which lines of code demonstrate polymorphism?
• 3/7 Recursion: Step through the recursive factorial method with the debugger, make it more fail-safe, and draw a box trace for fact(4).
• Example from class (March 19, 2019): binarySearch.txt (just the binarySearch method)
  TestSearch.java is a JUnit test class that creates a sorted array of integers and tests two search methods: linearSearch and binarySearch
• 3/19 Define the search method in your Bank class so that it uses as a helper method: binarySearch (modify above code to work with an array of Account rather than an array of int).
  • Keep in mind the precondition for binary search that the array must be sorted. Initially, you may just make sure that when you add accounts to the bank (using addAccounts method of Bank) do so in sorted ascending order of id numbers.
    • Later (not required for this exercise), we may either modify the addAccounts method so that it maintains the accounts in sorted order (i.e. insert the new account in a way that keeps the array sorted) or use a method to sort the accounts, e.g. one of those defined in: SortsClass.java
• 3/21 Exercises:
  • Optional exercise: Define the solveTowers method that we discussed today, without looking at the solution in the book/slides/link below.
  • Read and understand the recursive method fib (we will complete solveTowers next class but you may look at that too if you wish): Recursion.java
  • Recursive grammar exercise

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• Slides for Chapter 4: Data Abstraction: The Walls. This corresponds to chapter 3 of previous edition.
• Examples for Chapter 4
• ConcreteClock.java implements Clock.java (Interface)
• ConcreteFraction.java implements Fraction.java (Interface)
• Game (Explore) demo'd in class (based on Nick's RunManRun) that makes use of interfaces, inheritance etc: Explore2013v2.jar
  • Save the above JAR file, right-click on it and use a decompression program such as 7-zip to extract the files to a directory, then open the directory as a project in BlueJ.
• 3/26 Exercise: Define an ADT for your Bank named BankInterface which has the just the comments and header for each public method. Modify the header of your concrete class Bank so that it says: public class Bank implements BankInterface { ... }. Compile and run your existing tests in BankTest; it should work as before.
• Examples using a two-dimensional array:
  • RunManRun by Nicholas Miceli
  • Queens.java
• 3/28 Exercise:
  • Exercise using inheritance. You may refer to the example from class: ColoredSphere.java which extends Sphere.java (from chapter 4 examples). For Sphere's equals method (which we'll discuss more later) to compile, it needs the previously discussed closeEnough method in Comparison.java . A driver class that uses Sphere and ColoredSphere is TestSphere.java
• 4/2 Exercise: Second Exercise using inheritance
• 4/9: Exception handling exercise: using Bank program OR using Explore (Game) program
• 4/11: Define and test a sortAccounts method in your Bank class that calls one of the sorting methods of SortsClass.java. These sorting methods expect as parameter an array of type Comparable which is a predefined interface. For this to work, since you will be sorting an array of Account objects, your Account class needs to implement the Comparable interface (public class Account implements Comparable) and override the compareTo method that is promised by the Comparable interface:
  

  // compareTo: compare two Account objects.
  // Precondition: parameter o is an Object (of type Account)
  // Postcondition: return 0 if this.id is the same as o.id, -1 if this.id < o.id, 1 if this.id > o.id.
  @Override 
  public int compareTo(Object o)
  {
     if (o instanceof Account) {
  	...
     } 
  
     // o is not an Account ...
  }
  

Ted Murphy,72354,10256
Jane Smith,69713,4000
Edward Demsey,93757,75932

Ted Murphy,72354,102,56
Jane Smith,69713,40,0
Edward Demsey,93757,759,32

// Sample driver code (alternatively, infixExp and postfixExp can be attributes of a Calculator class)
String postfixExp = convertToPostfix(infixExp); 
int result = evaluatePostfix(postfixExp);