Unit 2

Here is the list of the unit 2 hacks.

Note: This is due Monday! Write your hacks in a Jupyter Notebook and then DM them to us over slack by Monday Morning at 8:00 AM. For full credit, all criteria in the hacks must be completed and show some originality.

Hack 1: (0.25)

Create a void method that takes an integer input and adds it to an ArrayList. Then, add a non-void method that is able to call a certain index from the ArrayList.

import java.util.ArrayList;

public class ArrayListExample {
    private ArrayList<Integer> integerList = new ArrayList<>();

    // Void method to add an integer to the ArrayList
    public void addToArrayList(int number) {
        integerList.add(number);
    }

    // Non-void method to get an element at a specific index
    public int getElementAtIndex(int index) {
        if (index >= 0 && index < integerList.size()) {
            return integerList.get(index);
        } else {
            throw new IndexOutOfBoundsException("Index is out of bounds.");
        }
    }

    public static void main(String[] args) {
        ArrayListExample example = new ArrayListExample();

        // Adding integers to the ArrayList
        example.addToArrayList(10);
        example.addToArrayList(20);
        example.addToArrayList(30);

        // Retrieving an element at a specific index
        int elementAtIndex = example.getElementAtIndex(1);
        System.out.println("Element at index 1: " + elementAtIndex); // This will print "Element at index 1: 20"
    }
}

ArrayListExample.main(null)

Element at index 1: 20

Hack 2: (0.25)

Create a simple guessing game with random numbers in math, except the random number is taken to a random exponent (also includes roots), and the person has to find out what the root and exponent is (with hints!). Use at least one static and one non-static method in your class.

import java.util.Random;
import java.util.Scanner;

public class MathGuessingGame {
    private static Random random = new Random();
    private int base;
    private int exponent;
    private double result;

    // Non-static method to generate a random number and its exponent
    private void generateRandomNumberAndExponent() {
        base = random.nextInt(10) + 1; // Random base between 1 and 10
        exponent = random.nextInt(5) + 2; // Random exponent between 2 and 6
        result = Math.pow(base, exponent);
    }

    // Static method to provide a hint about the random number and exponent
    private static void provideHint(int base, int exponent) {
        System.out.println("Hint: The number is " + base + " raised to the power of " + exponent);
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        MathGuessingGame game = new MathGuessingGame();

        System.out.println("Welcome to the Math Guessing Game!");
        System.out.println("Try to guess the number!");

        game.generateRandomNumberAndExponent();

        System.out.print("Enter your guess for the base: ");
        int guessedBase = scanner.nextInt();

        System.out.print("Enter your guess for the exponent: ");
        int guessedExponent = scanner.nextInt();

        if (guessedBase == game.base && guessedExponent == game.exponent) {
            System.out.println("Congratulations! You guessed it right. The number is " + game.result);
        } else {
            System.out.println("Sorry, your guess is incorrect.");
            provideHint(game.base, game.exponent);
        }

        scanner.close();
    }
}
MathGuessingGame.main(null)

Welcome to the Math Guessing Game!
Try to guess the number!
Enter your guess for the base: Enter your guess for the exponent: Sorry, your guess is incorrect.
Hint: The number is 7 raised to the power of 5

Hack 3: (0.25)

Create a class of your choosing that has multiple parameters of different types (int, boolean, String, double) and put 5 data values in that list. Show that you can access the information by givng some samples.

public class Person {
    private int age;
    private boolean isStudent;
    private String name;
    private double heightInCm;
    
    public Person(int age, boolean isStudent, String name, double heightInCm) {
        this.age = age;
        this.isStudent = isStudent;
        this.name = name;
        this.heightInCm = heightInCm;
    }
    
    public int getAge() {
        return age;
    }
    
    public boolean isStudent() {
        return isStudent;
    }
    
    public String getName() {
        return name;
    }
    
    public double getHeightInCm() {
        return heightInCm;
    }
    
    public static void main(String[] args) {
        // Creating an instance of the Person class with sample data
        Person person1 = new Person(25, true, "Alice", 165.5);
        
        // Accessing and printing the information
        System.out.println("Name: " + person1.getName());
        System.out.println("Age: " + person1.getAge());
        System.out.println("Is a student: " + person1.isStudent());
        System.out.println("Height (in cm): " + person1.getHeightInCm());
    }
}
Person.main(null)

Name: Alice
Age: 25
Is a student: true
Height (in cm): 165.5

Hack 4: (0.25)

Using your preliminary knowlege of loops, use a for loop to iterate through a person’s first and last name, seperated by a space, and create methods to call a person’s first name and a person’s last name by iterating through the string.

public class PersonNameParser {
    private String fullName;

    public PersonNameParser(String fullName) {
        this.fullName = fullName;
    }

    public String getFirstName() {
        // Initialize an empty string to store the first name
        String firstName = "";

        // Iterate through the full name character by character
        for (int i = 0; i < fullName.length(); i++) {
            char currentChar = fullName.charAt(i);

            // Break the loop when a space is encountered, indicating the end of the first name
            if (currentChar == ' ') {
                break;
            }

            // Append the current character to the first name
            firstName += currentChar;
        }

        return firstName;
    }

    public String getLastName() {
        // Initialize an empty string to store the last name
        String lastName = "";

        // Find the index of the last space in the full name
        int lastSpaceIndex = fullName.lastIndexOf(' ');

        // Iterate through the full name character by character, starting from the character after the last space
        for (int i = lastSpaceIndex + 1; i < fullName.length(); i++) {
            char currentChar = fullName.charAt(i);

            // Append the current character to the last name
            lastName += currentChar;
        }

        return lastName;
    }

    public static void main(String[] args) {
        // Create an instance of PersonNameParser with a full name
        PersonNameParser person = new PersonNameParser("John Doe");

        // Call the methods to get the first name and last name
        String firstName = person.getFirstName();
        String lastName = person.getLastName();

        // Print the extracted first name and last name
        System.out.println("First Name: " + firstName); // Output: "First Name: John"
        System.out.println("Last Name: " + lastName);   // Output: "Last Name: Doe"
    }
}
PersonNameParser.main(null)

First Name: John
Last Name: Doe

Unit 2 • 16 min read

Here is the list of the unit 2 hacks.

Hack 1: (0.25)

Hack 2: (0.25)

Hack 3: (0.25)

Hack 4: (0.25)