Question

In Java. Needing help with this homework assignment.

two maps. P15.3 Write a class Polynomial that stores a polynomial such as f(x) = 5x10 + 9x7-x-10 as a linked list of terms. A term contains the coefficient and the power of x. For example, you would store p(x) as (5,10),(9,7),(-1,1),(?10,0) Supply methods to add, multiply, and print polynomials. Supply a constructor that makes a polynomial from a single term. For example, the polynomial p can be constructed as Polynomial p new Polynomial (new Term(-10, 0)); ?.add(new Polynomial (new Term(-1, 1))); p.add(new Polynomial(new Term(9, 7))); p. add(new Polynomial (new Term(5, 10))); Then compute p(x) x p(x) Polynomial q p.multiply(p); q.printO P15.4 Repeat Exercise P15.3, but use a Map<Integer, Doubles for the coefficients.

The following is the class I need to write up and implement.

Answer 1

public class PolynomialTester
{
    public static void main(String[] args)
    {
        Polynomial p = new Polynomial(new Term(-10, 0));
        p.print();
        System.out.println("\nExpected: - 10.0");
        p.add(new Polynomial(new Term(-1, 1)));
        p.print();
        System.out.println("\nExpected: - 1.0x - 10.0");
        p.add(new Polynomial(new Term(9, 7)));
        p.print();
        System.out.println("\nExpected: 9.0x^7 - 1.0x - 10.0");
        p.add(new Polynomial(new Term(5, 10)));
        p.print();
        System.out.println("\nExpected: 5.0x^10 + 9.0x^7 - 1.0x - 10.0");

        Polynomial q = p.multiply(p);

        q.print();
        System.out.println("\nExpected: 25.0x^20 + 90.0x^17 + 81.0x^14 - 10.0x^11 - 100.0x^10 - 18.0x^8 - 180.0x^7 + 1.0x^2 + 20.0x + 100.0");
    }
}
------------------------------------------------------------------------------------
import java.util.LinkedList;
import java.util.ListIterator;

public class Polynomial
{
    LinkedList<Term> poly;

    public Polynomial()
    {

        poly = new LinkedList<Term>();

    }

    //Constructs a new polynomial with the given term

    public Polynomial(Term t)
    {
        poly = new LinkedList();
        //add the Term t to the LinkedList
        poly.addLast(t);

    }

    //Adds the polynomial such that the terms are in sorted order from highest power to lowest

    public void add(Polynomial p)
    {

        Term nextPoly = p.poly.getFirst();

        ListIterator<Term> iter = poly.listIterator();
        int num = nextPoly.getPower();

        //sort order
        while(iter.hasNext()){

            Term xp = iter.next();
            //order is determined by the power

            if(num == xp.getPower()){

                iter.remove();
                iter.add(new Term(xp.getCoefficient() + nextPoly.getCoefficient(), xp.getPower()));
                break;
            }

            else if (num > xp.getPower()){

                iter.remove();
                iter.add(nextPoly);
                iter.add(xp);
                break;

            }

            else if(!iter.hasNext()){

                iter.add(nextPoly);

            }

        }

        if(poly.isEmpty()){

            poly.add(nextPoly);

        }

        //finally add the new object to the LinkedList
        //poly.add(n,nextPoly);

    }

    //Multiplies the given polynomial with this one and returns the result

    public Polynomial multiply(Polynomial p)
    {

        Polynomial q = new Polynomial();
        ListIterator<Term> iter = p.poly.listIterator();
        ListIterator<Term> iter2 = p.poly.listIterator();

        while(iter.hasNext()){

            Term x = iter.next();
            double coffi= x.getCoefficient();
            int power = x.getPower();

            while(iter2.hasNext()){

                Term x2 = iter2.next();
                double coffi2= x2.getCoefficient();
                int power2 = x2.getPower();
                /*Term newTerm = new Term (coffi * coffi2, power + power2);*/

                q.add(new Polynomial(new Term (coffi * coffi2, power + power2)));

            }

            while(iter2.hasPrevious()){

                iter2.previous();

            }

        }

        return q;

    }

    //Prints the polynomial

    public void print()
    {

        int i = 0;

        //print everything from LinkedList
        for(Term x : poly){

            //This is to get the add or subtract sign
            char sign = ' ';

            sign = ((x.getCoefficient() + "").charAt(0) == '-') ? '-' : '+';

            if(sign == '+' && i == 0){

                System.out.print(" " + x.toString() + " ");

            }

            else{

                System.out.print(sign + " " + x.toString() + " ");

            }

            ++i;
        }

    }
}

------------------------------------------------------------------------------------------------
public class Term
{
    private double coefficient;
    private int power;

    // constructor to initialize a single term with a given coefficient and power

    public Term(double coefficient, int power)
    {
        this.coefficient = coefficient;
        this.power = power;
    }

    public double getCoefficient()
    {
        return coefficient;
    }

    public int getPower()
    {
        return power;
    }

    //Multiplies two coefficient together and returns the result

    public Term multiply(Term t)
    {
        return new Term(coefficient * t.coefficient, power + t.power);
    }

    //Adds the term to this term if the powers are the same

    public void addIfSamePower(Term t)
    {
        if (t.power == power)
        {
            coefficient += t.coefficient;
        }
    }

    // Returns a string representation of the term with a ^ representing the exponent

    public String toString()
    {
        if (power == 0)
        {
            return Math.abs(coefficient) + "";
        }
        else if (power == 1)
        {
            return Math.abs(coefficient) + "x";
        }
        else
        {
            return Math.abs(coefficient) + "x^" + power;
        }
    }
}