CodeHS Unit 4 Rectangle Class

Questions and Answers

What is the formula used to calculate the distance in miles between two geo locations?

return Math.sin(latitude)

return distanceFrom(other) * KM_PER_MILE (correct)

return Math.cos(longitude)

return arcLength * RADIUS (correct)

What are the fields in the TextMessage class?

message, sender, receiver

What is the default maximum number of players in the Player class?

What does the getArea method in the Circle class return?

Area of the circle Signup and view all the answers

The PI value in the MathOperations class is static.

False Signup and view all the answers

Which methods in the Product class are overloaded?

All of the above Signup and view all the answers

The method to get the winner of Rock, Paper, Scissors is called ___

getWinner Signup and view all the answers

Match the following classes with their primary function:

Messages = Handles text message logic Fraction = Represents fractions with numerators and denominators Circle = Calculates area based on the radius Player = Tracks the number of players in a game Signup and view all the answers

What is the purpose of the Rectangle class?

To create rectangle objects that have width and height. Signup and view all the answers

What method is used to get the area of a Rectangle object?

getArea Signup and view all the answers

What is the output of the RectangleTester program when a rectangle with width 5 and height 12 is created?

Rectangle with width: 5 and height: 12 Signup and view all the answers

The CoinFlips class simulates flipping a coin a specified number of times.

True Signup and view all the answers

What do the variables named 'Bart' and 'Lisa' represent in the Messages class?

TextMessage objects Signup and view all the answers

Which of the following classes encapsulates properties of a flower?

Flower Signup and view all the answers

What method in the Dog class returns a description of the dog?

toString Signup and view all the answers

How is the distance calculated between two GeoLocation objects?

Using the distanceFrom method Signup and view all the answers

What does the Student class represent?

It represents a student with first name, last name, grade level, and GPA. Signup and view all the answers

The _____ method returns the name and grade level of the student.

toString Signup and view all the answers

The BaseballPlayer class has a method to calculate the batting average.

True Signup and view all the answers

What is the output of the Fraction class's toString method when the fraction is 1/2?

1/2 Signup and view all the answers

Study Notes

Rectangle Class

Rectangle Class Implementation: Contains attributes for width and height, methods for area and dimensions, and overrides toString() for a descriptive output.
RectangleTester Example: Tests Rectangle by creating an instance and printing its dimensions.

Method Calling in Rectangle Class

Getters for Rectangle Class: getHeight(), getWidth(), and getArea() methods return corresponding attributes.
RectangleTester Use: Creates a rectangle instance and prints its dimensions and area using the defined methods.

Point Class Usage

Point Class Features: Stores x and y coordinates, includes a method to move the point and overrides toString() to display position.
PointTester Example: Demonstrates creation, movement, and printing of Point objects.

Student Class Implementation

Attributes of Student Class: Contains firstName, lastName, and gradeLevel, and includes a toString() method for representation.
StudentTester Demonstration: Creates student instances and prints their information.

Text Message Class

TextMessage Class Design: Defines sender, receiver, and message, with a toString() method for formatted output.
Messages Example: Instantiates and prints messages between Bart and Lisa.

Coin Flip Simulation

CoinFlips Class: Simulates FLIPS number of coin tosses, counting heads and tails outcomes, and calculates percentages.
Randomizer Usage: Generates random boolean values for coin toss outcomes.

Longest Streak Tracker

LongestStreak Class: Tracks longest consecutive "Heads" results from flips, resetting streak upon a "Tails" outcome.
Implementation of Random Flips: Uses Randomizer for generating coin toss results.

Distance Calculation Between Locations

GeoLocation Class: Contains latitude and longitude data; includes method for distance calculation based on spherical law of cosines.
HowFarAway Program: Prompts user for location coordinates and calculates distance between two geographical points.

Triangle Class Details

Triangle Attributes: Initialized with width and height, includes toString() for formatted output.
TriangleTester Usage: Tests triangle creation and output representation.

Flower and Dog Class Implementations

Flower Class: Encapsulates flower details (name, color, genus, species) with a descriptive toString().
Dog Class: Represents dog breed and name, with a formatter in toString() to display information.

Student Class Enhancements

GPA Attribute Addition: Introduces a GPA field to student class with getter/setter methods and honors student determination.
StudentTester Expansion: Logs output for student GPA and honors status checks.

Pizza Class Construction

Pizza Object Design: Comprises type, toppings, and size with a formatted string representation.

Fraction Class Implementation

Fraction Class: Represents rational numbers with numerator and denominator; includes toString() and getter/setter methods.

Batting Average Calculation

BaseballPlayer Class: Stores player stats, includes a method to calculate batting average, and formatted output for player performance.

Static Player Management

Player Class: Maintains a static count of players, with a maximum limit and features construction to increase player count upon instantiation.

Unit Circle Calculation

UnitCircle Class: Computes cosine and sine for angles in radians, displaying results for each calculated angle.

Text Message Getter Methods

TextMessage Class: Includes getter methods for sender, receiver, and message content, facilitating information retrieval.

Fraction Getter/Setter Implementation

Fraction Class Enhancements: Adds methods to retrieve and modify numerator and denominator values, improving data encapsulation.### Game Full Function
gameFull() checks if the total number of players has reached the maximum limit.
Returns true if totalPlayers is greater than or equal to maxPlayers.

Circle Area Calculation

Class CircleTester tests the area calculation of circles with specific radii.
Creates a Circle object with radius 5 and prints its area.
Creates another Circle object with radius 12 and prints its area.
Class Circle defines a static constant PI for mathematical calculations.
getArea() method calculates the area using the formula: Area = π * radius².

Rock, Paper, Scissors Winner Logic

Method getWinner() determines the result between the user's choice and the computer's choice.
If both choices are the same, it returns "Tie".
Implements rules for winning: rock beats scissors, scissors beats paper, paper beats rock.

Rock, Paper, Scissors Game Implementation

Class RockPaperScissors facilitates interaction with the user through console inputs.
Utilizes constants for win messages and options (rock, paper, scissors).
Continues taking user input until a null value is provided.
Randomly generates the computer's choice using Randomizer.

Randomizer Class

Singleton design pattern ensures only one instance of the Random object exists.
Provides various random number generation methods:
- nextBoolean(), nextInt(min, max), and nextDouble(min, max).
Allows customization of probability for boolean outcomes.

Product Method Overloading

Class Product defines multiple overloaded methods to calculate products of different data types.
Supports operations for:
- Two integers
- Two doubles
- Integer and double in either order
- Three integers or three doubles.
Each method outputs the product result after performing the calculation.

Variable Scope in Math Operations

Class MathOperations illustrates usage of local and instance variables.
Defines various mathematical operations including sum, difference, product, circleCircumference, and circleArea.
Prints out values of PI, and parameters within method scopes to demonstrate variable accessibility.
Calculates circumference and area by invoking the respective formulas.

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Test your knowledge of the Rectangle class from CodeHS Unit 4 with this flashcard quiz. Understand how to create and utilize the Rectangle class in Java by reviewing the provided code snippets. Ideal for beginners looking to reinforce their Java programming skills.