Final Review

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Final Details

Monday, December 11th

7:00pm – 10:00pm HCC 1325

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Sections Covered - Detailed View 1.1-1.2, 1.4-1.6 2.1-2.6 3.1-3.3, 3.6-3.8 [covered 3.4, 3.5 in class] 4.1-4.4 [covered 4.5 in class] 5.1-5.5, 5.7-5.8 [(basically) covered 5.6 in class] 6.1-6.5, 6.7, 6.8 [covered 6.9 in class] 7.1-7.2, 7.6-7.7 [covered 7.4 in class] 8.1-8.5 9.1-9.5 10.1-10.6 11.1-11.3 some parts of 12 covered in class notes

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Sections Covered - Broadly

Chapters 1-11 (except for Graphics track) … with minor exceptions…

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Other Topics (from before midterm) Running time / Big O notation Working with references handout

including null/this Merge sort Command line arguments printf

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Other Topics (after midterm)

More detailed treatment of some topics polymorphism (e.g. covered Collections) file output (e.g. covered buffers and generic

Writers) File input

Call Stack Scanning tokens Regular Expressions

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Chapter 1

Computer processing The Java Programming Language Program Development Object-Oriented Programming

(very basic)

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Chapter 2

Character Strings Variables and Assignment Primitive Data Types Expressions Data Conversion Interactive Programs

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Chapter 3

Creating Objects The String Class Packages Formatting Output

(plus more detailed coverage of printf) Enumerated Types Wrapper Classes

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Chapter 4

Anatomy of a Class Encapsulation Anatomy of a Method

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Chapter 5

The if Statement and Conditions Other Conditional Statements Comparing Data The while Statement Other Repetition Statements

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Chapter 6

Software Development Activities Identifying Classes and Objects Static Variables and Methods Class Relationships Interfaces Method Design Testing

(covered the same material in class)

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Chapter 7

Declaring and Using Arrays Two-Dimensional Arrays The ArrayList Class

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Chapter 8

Creating subclasses Overriding methods Class hierarchies Inheritance and visibility Designing for inheritance

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Chapter 9

Polymorphism polymorphic references through inheritance through interfaces

Searching linear search binary search

Sorting insertion sort selection sort merge sort

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Chapter 10

Exception Handling The try-catch Statement Exception Classes I/O Exceptions

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Chapter 11

Recursive Thinking Recursive Programming Using Recursion

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Running Time – Big-O

For a parameter n… e.g. the length of a string or size of an array

… count the number of steps performed… loop through n elements = n steps loop inside a loop = n2 steps

Ignore constants… coefficients… 3n + 2 steps = O(n) n2 /2 steps = O(n2) “cutting problem in half at each step” = O(log n)

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Working with References

null reference Object variable not assigned anything When does this cause an exception?

this reference When does this simplify code?

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File I/O

Where do the exceptions happen? How do we handle them?

Why do we want to buffer? How do we buffer? Using Scanner

with default tokens with defined tokens

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Regular Expressions

Given regular expression yes/no matching questions give informal description

Given informal description write regular expression pass appropriately to Scanner

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What Kind of Questions?

Look at the exercises in the text finding errors in code finding differences in code explaining/defining concepts predicting output of code writing methods or classes specifying/justifying design from requirements

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What Kind of Questions?

Similar format for lecture material e.g. specify running time e.g. find null reference problem

Using regular expressions Predicting tokens parsed Describe call stack

including exceptions explain stack trace

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It May Be on the Test if…

It is in the text It is in the lecture notes It is something I said in class or wrote on the

blackboard It was part of a lab/assignment

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What Code Do You Need to Know? Officially: everything as per previous slide Unofficially:

I try to only assume you know “important” methods and classes

… but I decide what is “important” in general… little used methods that occur rarely

in the notes will be given implicitly but you should know enough code to solve

problems without help/look-up

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Examples

There will be definitions (again) abstract class checked exception final method overridden method

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Examples

There may be explanations required… Explain why a static method cannot refer to an

instance variable. Give two differences between an abstract class

and an interface.

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Examples

Draw a UML diagram for a single class hierarchy representing these animals, with abstract classes grouping animal types parrot gorilla horse bat penguin

Add an interface for flyers

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Examples

Correct the problemsFlyer polly = new Parrot();

Animal koko = new Gorilla();

Gorilla junior = koko.makeOffspring();

polly.layEgg();

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Examples

Define appropriate classes and public methods for the given requirements. Every salesperson will be assigned a unique ID

number, and a numbered office with a phone. Salespeople will sell vacuum cleaners at a fixed price. When inventory runs out, the top salesperson will be designated employee of the month.

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Examples

Find the exception in this code, and handle it.public static void main(String[] args)

{

FileWriter fileout = new FileWriter(“names.txt”);

if(fileout!=null)

fileout.write(“John Smith”);

else

System.out.println(“No name written to file”);

}

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Examples

Find the exception in this code, and handle it.public static void main(String[] args)

{

Student s = new Student(4533453,”tsmith”);

String fname = s.getFirstName();

System.out.println(fname);

}

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Examples

Given this information in file.txt:

7 | 5 | 5p ,| 4 Write the code that will print these tokens to

the screen using a Scanner/delimiter: “7 | 5 | 5” and “ , | 4” “7 | “ and “ | “ and “p ,| 4”

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Solution

Scanner filein = new Scanner(

new File(“file.txt”)

).useDelimiter(“p”);

while(filein.hasNext())

{

System.out.println(filein.next());

}

“5”

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Examples

Yes or no expression matching [1-7]*a? 43 (17)+(17a)? 17a [abc][def](di)? bed [123]+(45)?a* 12312345aaaa [ab][bc][cde]* abcde [A-C]DEF? ABCDE [truck].[stop]+ trstopstop

yes

yes

yes

no

no

yes

no

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Examples

Describe the strings matching the expressions (cat)+ [cat][cat] cat? [ca]?t* (c?a+)t? [c-t]a?[c-t]*

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Examples

What is the value in variable temp after:int temp = 30;String stemp = temp + “12”;temp = temp + Integer.parseInt(stemp);

Again:Collection<Integer> l = new

ArrayList<Integer>; int temp = 40;l.add(40);temp = l.size();

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Examples

Write a method that picks a random character in the string “string”.

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Examples

What is wrong with this? How can it be corrected?

int count=1,max=0;

while(count=max)

{

System.out.println(count);

count-=2;

}

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Examples

A LinkedList implements Collection Write a method that adds every word in the

sentence “This is a sentence” to a LinkedList, then prints the size.

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Examples

Given double[] input, write a method that returns the highest value

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Examples

Write a class NamedArrayList that extends ArrayList by adding a name for the array list in the first position.

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Examples

What is wrong with these declarations:

char[] chars = {“d”, “a”, “b”}; String[] = new String[5]; Scanner[] sc = new Scanner(5);

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Examples

Write a recursive function that returns true if the input is a power of 3.

Write a recursive function that returns true if a string contains only the letter ‘s’.