Units 6 - 10

// Unit 7
import java.util.*;

public class hack1{
    public static void main (String[] args){
        ArrayList<String> cool = new ArrayList();
        System.out.println(cool.size());
    }
}
hack1.main(null);

0

import java.util.*;

ArrayList<String> color = new ArrayList();
color.add("red apple");
color.add("green box");
color.add("blue water");
color.add("red panda");

for(int i = 0; i <= color.size(); i++){
    if(color.get(i).contains("red")){
        color.remove(i);

    }
}
System.out.println(color)

[green box, blue water]

Unit 7 Vocab

• Array List - Similar to an array, however the length of the list can be modified when need be
  • Can iterate through it similar to an array, however putting and removing items are different syntax

public class Test {

    public static void main(String[] args) {
  
        String[][] arr = { // two indexes, to help store data in a 2D model
            { "Atlanta", "Baltimore", "Chicago" },
            { "Australia", "Boston", "Cincinnati" },
            { "Austin", "Beaumont", "Columbus" }
        };

        String longest = arr[0][0]; //defining the longest array at the moment

        for(int row = 0; row < arr.length; row++) { //incrementing through each part to find largest string
            for(int column = 0; column < arr[row].length; column++) {
                if (arr[row][column].length() > longest.length()) {
                    longest = arr[row][column];
                }
            }
         }

        System.out.println(longest); 

        // Use nested for loops to find the longest or shortest string!
        System.out.println("Use nested for loops to find the longest or shortest string!");
        
    }

 }
Test.main(null);

Cincinnati
Use nested for loops to find the longest or shortest string!

Unit 8 Vocab

• Usage of a nested for loop to iterate through a 2D Array, through each "cell"

• Declared with two brackets next to name

public class Animal {
    protected double mass;
    protected double lifespan;
    public Animal(double mass, double lifespan) {
        this.mass = mass;
        this.lifespan = lifespan;
    }
    public void sound() {
        System.out.println("sound");
    }

    public void die(boolean a) {
        System.out.println("the cat is dead: " + a); //method to be overloaded
    }
    public class Dog extends Animal {
    
        protected String color; 
        
        public Dog(double mass, double lifespan, String color) {
            super(mass, lifespan);
            this.color = color;
        }
        @Override
        public void sound() {
            System.out.println("woof");
        }
    }
    public class Cat extends Animal { //make  another subclass for Cat that extends off of Animal 
    
        protected String breed; 
        
        public Cat(double mass, double lifespan, String breed) {
            super(mass, lifespan);
            this.breed = breed;
        }
        @Override
        public void sound() { //overrides the sound
            System.out.println("meow");
        }

        public void die(boolean a, boolean b) { //method overloading
            System.out.println("the cat is dead: " + a + b);
        }
    }
}

Unit 9 Vocab

• Inheritance/extends takes aspects of an existing class and replicates it within another class using the extends method, simplifying code by a lot.
• Subclass/Super - A subclass constructor forms after extending a previous class, and using the super(); method will take a method and replicate it in the new class.
• Overloading - When you use the same method name in a class each with different parameters.
• Override - When a subclass has the same name and parameters as the parent class
• Polymorphism - any of overloading, overriding, late bindingMultiple methods with the same name but different parameters

No code for lesson 10

• Recursion - method calling itself again, similar to a loop
• Base case - the condition passed that is needed to be reached to end the loop
• Binary search - Split the array in half and then continue doing so until the value is found
• Selection - finds minimum element from unsorted part and puts it at end of sorted part
• Merge - splits array into 2, calls it self into two sorted halves, and then merges all the havles back into arrayList