Classes are a blueprint for instantiating objects. An object is an istance of a class, a class defines an abstract type, methods are the behaviors you get objects to perform. Constructors create the object, are a special method for object instantiation, default constructor has no arguements. Accessor methods are getters and setters, which allow you to get values of variables and return a copy, or edit a variable.

public class StepTracker {
    // initialize variables
    private int minActiveSteps;
    private int totalSteps;
    private int numTotalDays;
    private int numActiveDays;

    // set default construct
    public StepTracker(int minActiveSteps) {
        this.minActiveSteps = minActiveSteps;
        this.totalSteps = 0;
        this.numTotalDays = 0;
        this.numActiveDays = 0;
    }

    // once per day, increment steps, days, and possibly active
    public void addDailySteps(int numSteps) {
        this.totalSteps += numSteps;
        this.numTotalDays++;

        if (numSteps >= this.minActiveSteps) {
            this.numActiveDays++;
        }
    }

    // getter
    public int activeDays() {
        return this.numActiveDays;
    }

    // calculate
    public double averageSteps() {

        if (numTotalDays == 0) {
            return 0.0;
        } else {
            return (double) this.totalSteps/this.numTotalDays;
        }
    }
}

// FRQ #2
public class StepTracker {
   
    private int totalSteps;
    private int minimumSteps;
    private int days;
    private int activeDays;
    
    public StepTracker(int min){
        minimumSteps = min;
        totalSteps = 0;
        days = 0;
        activeDays = 0;
    }

    public void addDailySteps(int steps){
        totalSteps += steps;
        days++;
        if (steps >= minSteps){
            activeDays++;
        }
    }

    public double averageSteps(){
        if (days == 0){
            return 0.0;
        } 

        else{
            return (double) totalSteps / days;
        }
    }


    public int getActiveDays(){
        return days;
    }

}

Hack

public class Cow {
    public String type;
    public String sound;
    public int milk;

    
    public Cow(String type, String sound, int milk) {
        this.type = type;
        this.sound = sound;
        this.milk = milk;
    }

    public String getType() {
        return this.type;
    }

    public String getSound() {
        return this.sound;
    }

    public static void main(String[] args) {
        Cow tommy = new Cow("white", "moo", 5);
        Cow jacky = new Cow("black", "meow", 3);
        System.out.println(tommy.getSound());
    }
}
Cow.main(null);

moo