Cantilever

//Assumes that the ball is on the edge closest to table
import java.util.*;
public class Cantilever {
    private final double LEN = 0.3; //length of each slat in meters. Also 30 cm
    private final double MASS = 0.036; //mass of each slat in kg. Also 36g
    private final int NUM_SLATS = 20; //number of slats to be used
    private double ball; //mass of extra "ball" on top of cantilever in meters. 0.05, 0.1, or 0.2kg
    private ArrayList<Double> prevDist = new ArrayList<>(); //list of all previous distances from ledge
    private double finalCOM = 0; //final center of mass
    private double[] balls = {0.005, 0.01, 0.02}; //different masses that ball could be
    private double totalSum;
    public Cantilever(){
        for (int h = 0; h < 3; h++){
            ball = balls[h];
            for(int n = 1; n <= NUM_SLATS; n++){//n is the nth slat
                double distSum = 0;
                distSum += ball*(getPrev(n-1) + LEN) + n*MASS*(LEN/2);
                for (int j = 0; j < prevDist.size(); j++){
                    distSum += (j + 1)*prevDist.get(j)*MASS;
                }
                distSum /= (n*MASS + ball);
                prevDist.add(LEN - distSum);
                finalCOM = LEN - distSum;
        }
        System.out.println("Mass of ball: " + ball*1000 + " grams.");
        printLedgeDistances();
        System.out.printf("The final center of mass is %.2f centimeters.\n", finalCOM);
        System.out.printf("Score: %.2f\n", ball*1000*(totalSum+LEN));
        System.out.println();
        prevDist.clear();
        }
    }

    //Gets sum of previous distances up to the nth previous distance (inclusive)
    public double getPrev(int n){
        double sum = 0;
        if (n == 0){
            return 0;
        } else {
            for (int i = 0; i < n; i++){
                sum += prevDist.get(i);
            }
            return sum;
        }
    }

    //sums all of the ledge distances to get total distance
    public double sumAll(){
        double totalSum = 0;
        for (Double dist : prevDist){
            totalSum += dist;
        }
        return totalSum;
    }

    public void printLedgeDistances(){
        totalSum = 0;
        for(int j = 0; j < prevDist.size(); j++){
            System.out.printf("Ledge %d: %.2f centimeters\n", (j+1), prevDist.get(j)*100);
            totalSum += prevDist.get(j)*100;
        }
        System.out.printf("Total distance: %.2f centimeters.\n", sumAll()*100);
    }

    public static void main(String[] arguments){
        Cantilever c = new Cantilever();
    }
}