• Objects are instances of Classes, which are like a template of data (attributes) and functions (methods)
• Objects are created and their contents, which are pulled from the class, is used in code

public class Tennis { // class creation
    
    public void printPlayers(){   // simple method
        System.out.println("Nadal");
        System.out.println("Federer");
        System.out.println("Djokovic");
    }

    public static void main(String[] args){  // main class that runs
        Tennis myObject = new Tennis();    // CREATING AN OBJECT FROM TENNIS CLASS
        myObject.printPlayers();      // Use dot notation to reference methods/attributes from the class that the object is initialized from
    }   

}

Tennis.main(null);

• Extending another Class inherits all of the methods and attributes from that class.
• Class being extended is called the super class
• Class extending is called subclass

public class TennisTwo extends Tennis{  // extending Tennis class
    public TennisTwo(){    // TennisTwo now has all of Tennis's methods
        super();
    }

    public static void main(String[] args){  // main class that runs
        TennisTwo myObjectTwo = new TennisTwo();    // CREATING AN OBJECT FROM TENNISTWO CLASS
        myObjectTwo.printPlayers();      // Use dot notation to reference methods/attributes from the INHERITED class
    }
}

TennisTwo.main(null);

Comparing Objects

• equals and hashCode methods can be used to compare objects
• equals method compares equality of two objects ### Example

import java.io.*;
 
class Pet {

    String name;
    int age;
    String breed;
 

    Pet(String name, int age, String breed)
    {
        this.name = name;
        this.age = age;
        this.breed = breed;
    }
}

public class Main {
 
    public static void main(String args[])
    {
 
        Pet dog1 = new Pet("Snow", 3, "German Shepherd");
        Pet cat = new Pet("Jack", 2, "Tabby");
        Pet dog2 = new Pet("Snow", 3, "German Shepherd");
 
        System.out.println(dog1.equals(dog2));
    }
}

Main.main(null);

false

FRQ

public int scoreGuess( String guess )
{
    int val = 0;
    int len = guess.length();
    for( int i = 0; i <= secret.length()-len; i+=1)
    {
        String ck = secret.substring( i, i+len );
        if( ck.equals(guess) )
            val++;
    }
    return val*len*len;
}

public String findBetterGuess(String guess1, String guess2 )
{
    int a = scoreGuess( guess1 );
    int b = scoreGuess( guess2 );
    if( a > b ) return guess1;
    if( b > a ) return guess2;
    if( guess1.compareTo( guess2 ) > 0 )
    return guess1;
    return guess2;
}