Category Archives: Computer Science

Jeroo Python While Loop

Cross the Lake with a while loop

custom method go around lake

Objective: Make a jeroo walk around the perimeter of the lank, on the land side. Use a custom method
download the island file

Class Relationships involving interfaces and Abstract Classes

Two Caveats

all instance variables must be explicitly written as “private”
Declare ArrayList’s as type “list”:
1. List<Integer> blahBlah = new ArrayList<Integer>()

The classes below represent different ways of representing mathematical concepts like MathExpressions, Fractions etc. and they all implement the Mathable interface.

public abstract class GraphicalMathObject

methods

public abstract void displayGraphicalRepresentation() ;

public class Fraction extends GraphicalMathObject

This class is used to represent Fractions

Instance Variables

private int numerator
private int denominator

Constructor : The constructor should initialize both instance variables

public Fraction(int num, int denom)

Methods

public void displayGraphicalRepresentation() ; (just print out ” I’m a fraction -displayGraphicalRepresentation()”. This is the method that renders a graphical representation of the fraction .
$fraction-matching$
private int getGCF() //returns the GCF of numerator and denominator
public void simplify()//simplifies the fraction. Note: you must call getGCF()
public Fraction clone() //return a clone of the current object (** Extra credit…research this) ( link )
plus all of the methods in Mathable (Described at bottom)

public class MathExpression extends GraphicalMathObject

This is a class that is used to represent mathematical expressions like 3x²or 5x²y² . It contains the methods and variables described below and it must implement Mathable

Instance Variables

private int coefficient
private List<String> variables
private List<Integer> powers

NOTE: you should use the following sytnax

Declare ArrayList’s as type “list”:

List<Integer> blahBlah = new ArrayList<Integer>()

Constructor : You can decide how to write the constructor.

Just be sure to initialize the instance variables

methods implement all methods of the Mathable Interface in ways that make sense for this class. The idea with Mathable is that you should be able to tell if the objects are either equivalent, exactly the same and that you should be able to return a String representation (data) that uniquely identifies the given mathematical expression.

public void addTerm( String term , int power) ) // This is used to represent multiplication, actually and this method adds a term with a power to the object’s list of variables and power to the list of powers. You can not assume that the term does not yet exist in the expression .
For instance, if the original term were 3x⁵ and the object called addTerm("y", 6) the object would then be 3x⁵y⁶. Or for another example, if the original term is 2x³z⁶, and addTerm("z", 5) the object would be 2x³z¹¹.
public void displayGraphicalRepresentation() ; (just print out “I”m a MathExpression.: displayGraphicalRepresentation()”). This is the method that draws the MathExpression on the screen like:
plus all of the methods in Mathable

Examples

3x²y⁵

coefficient: 3

variables : [ “x”, “y”]

powers : [ 2, 5]

x¹y¹¹

coefficient: 1

variables : [ “x”, “y”]

powers : [ 1, 11]

3y²x⁵

coefficient: 3

variables : [ “y”, “x”]

powers : [ 5 , 2]

Interface : Mathable

public String getData( ) ; represents core mathematical information that defines current object.
public boolean exactlyEquals(Mathable other) ;
public boolean isEquivalent(Mathable other) ;

Walk the Lake (custom Method)

method main(){
Jeroo Russell  = new Jeroo(10,3, EAST );

Russell.pickTossAndHop();
Russell.pickTossAndHop();
Russell.pickTossAndHop();
Russell.pickTossAndHop();
Russell.pickTossAndHop();
Russell.pickTossAndHop();
Russell.pickTossAndHop();
Russell.pickTossAndHop();
Russell.pickTossAndHop();
Russell.pickTossAndHop();
Russell.pickTossAndHop();
Russell.pickTossAndHop();
Russell.pickTossAndHop();
Russell.pickTossAndHop();
Russell.pickTossAndHop();
Russell.pickTossAndHop();
}

method main(){

Jeroo Russell = new Jeroo(10,3, EAST );

Russell.pickTossAndHop();

}

def pickTossAndHop( self ):
	pick();
	toss();
	hop();

def pickTossAndHop( self ):

pick();

toss();

hop();

Intro To Java Assignments (2013-14)

Arrays II

Arrays in Demo
Test : June 10th/11th (Arrays and two dimensional arrays)
Two Dimensional Arrays
The problem with Arrays
- Array 3
Array 2 (codingbat) Do any 18 questions. You can get extra credit for doing any of the last 4. EOD Sunday May 31st
- All students must do sum67
Array Fun 2 (due by EOD Tuesday May 13rd )
Array Fun 1 (email to me by EOD Tuesday May 6th)

Arrays

short circuiting
Array 1 Coding Bat type questions
default values of arrays
arrays in memory(value vs reference)
swapping values in an array without creating a new array like this coding bat problem–assuming you didn’t make a new array
Coding Bat : Array 1 (Thursday April 24th-that’s day of the 2nd class after the April break)
Short Circuiting

April 2nd

Test (April 2nd/3rd)
All coding bat warm up and String 1’s must be completed by then
Strings immutable, codingbat.com

Strings (the basics)

String Cheat Sheet

String str ="ABCDEFG"

String firstLetter = str.substring(0,1)

String firstTwoLetters = str.substring(0,2)

String lastLttr = str.substring(str.length() -1)

String last_2_lttrs = str.substring(str.length() -2 )

String middle_lttr = str.substring(str.length()/2 , str.length()/2 +1)
Unit 2

Introduction to Strings
String Assignments #1
Coding Bat – Warm up 1 (now do the ones involving Strings)
Coding Bat -STrings 1

Extra credit: Looping over Strings

String Loops Review (word doc) **
String Loops 1
String Loops 2 (must do)
String Projects #1 do the (Validate User Input Project)
testcases_validate_form
Required Coding Bat Problems
Some Practice Problems

Unit I
Deadline the day you return from feb break

Coding Bat
Warm up I – Skip all things that have to do with Strings (for now)
Logic 1 – (all)
logic 2 ( any 5)

Midterm Quiz

*Wed/Thursday 21st/22nd

definitions:
- pass by value
- pass by reference
C++ memory usage (see last asssessment) . Yes, pretty much same questions with different numbers
floating point error
understand of whether the following data types are pass by value vs reference in Java
- int
- double
- boolean

cross-the-bridge

Objective: Your goal is get your jeroo onto the right side of the island. Note that the red areas are nets. You must toss() a flower onto the net before you can go on the net.. You will need the following island file .

Walk-the-lake

Monsoon rains have created a lake in the middle of Santong Island. Furthermore, that lake contains an island. Two Jeroos were separated by the rains. One is on the main part of Santong Island, but the other is on the island in the middle of the lake. The goal of this program is to have each Jeroo explore the shoreline of the lake.

Each Jeroo starts with one flower and the lake immediately to its right.
Each Jeroo starts by planting a flower then traveling, keeping the lake on its right, until it returns to the flower. The Jeroo then picks the flower.
(only plant 1 flower, at starting point…and make 1 lap until you are back at that flower)
Have the Jeroo on the main part of Santong Island walk the shore first.
then have the one on the lake’s island walk the shore

Download Walk the Lake (This has several maps, choose any 1)

Acknowledgement

This problem is adapted from one that was created originally by Erica Eddy of The University of Wisconsin – Parkside.

Or you can try walk the lake using loops using this map and Jeroo assignment

Jeroo Custom Methods

Do you ever wish that you could make your Jeroo turn around 180 degrees?

Example 2 of a Custom Method to “Go Around a net”

You can download the files for the animation below here

custom methods

Beautify The Island

Objective: Your goal is to have a jeroo beautify the Island. Instantiate a jeroo with 8 flowers in its pouch and have the jeroo plant the flowers in the pattern below Download these beginning-activites

Bank Class

You have a lot of flexibility in creating this class, but here is what it should be able to do

manage an array list of Accounts that could be any kind of account private ArrayList<Account>

Functionality that you must implement.

It’s up to you to decide how to implement the functionality below. You will only lose credit if your methods clearly make no sense, have bad variable names/method names.

add an Account (of any type)
remove an account by
- account id
- owner (a Person object)

The functionality above ^^ can be implemented in any efficient way that makes sense, but it must be implemented. I am leaving that part up to you!

Some Specific Required Methods
- public ArrayList<Person> topAccountOwners(double cutoff)
  - this method returns an ArrayList of the owners whose accounts have at least cutoff amount of balance
- public void nightlyUpdate()
  - this runs through the accounts and if account is a SavingsAccount , then it calls that object’s recordDailyBalance() method (You are going to have to use instanceOf and then cast those accounts to a SavingsAccount )
- public Account topBalance() ; returns the Account object with the greatest balance
- public Account[] allWithinRange(double min, double max) returns an array of Accounts whose balances range from min to max , inclusive
- public boolean transfer( double amount, int accountIdFrom , int accountIdTo) ; this method transfers money from the one account to the other. If the accountIdFrom does not have enough $$, this method returns false.
- public void monthlyUpdate()
  - this runs through the accounts and if
  - account is a SavingsAccount , then it calls that object’s updateInterestPayment() method
- ** extra credit ArrayList<Account> sortByAmount()
  - this method returns an arraylist of Accounts sorted by amount in the account

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Category Archives: Computer Science

Jeroo Python While Loop

custom method go around lake

Class Relationships involving interfaces and Abstract Classes

public abstract class GraphicalMathObject

public class Fraction extends GraphicalMathObject

public class MathExpression extends GraphicalMathObject

Examples

Interface : Mathable

Walk the Lake (custom Method)

Intro To Java Assignments (2013-14)

Arrays II

Arrays

Strings (the basics)

String Cheat Sheet

Midterm Quiz

cross-the-bridge

Walk-the-lake

Jeroo Custom Methods

Beautify The Island

Bank Class

Bank Class

Functionality that you must implement.

public abstract class GraphicalMathObject

public class Fraction extends GraphicalMathObject

public class MathExpression extends GraphicalMathObject

Examples

Interface : Mathable

Arrays II

Arrays

Strings (the basics)

String Cheat Sheet

Midterm Quiz

Bank Class

Functionality that you *must* implement.

Functionality that you must implement.