Serge Metellus

Piet in the requirements it states that the add and insert have to be in the Polynomilal class which i explained earlier. Also, in the requirements it says that comparable is implement on the exponents ONLY meaning it does not matter what the coefficient is. You seem irritated but i tried to explain everything to you and  blatantly ignored me again and again. also when the coefficient is zero the entire term is zero so AGAIN it does not matter

Okay but insert has to be in the polynomial class not the Node class

that is exactly what i have been doing because those are the only two methods i have left to do in this entire program.

Carey Brown wrote:
public class Node2 { static Node2 root; int payload; Node2 next; public static void main( String[] args ) { } public Node2( Node2 next, int payload ) { this.next = next; this.payload = payload; } public void insert( Node2 n, int payload ) { Node2 prev = null; Node2 curr = root; while( curr != null && payload >= curr.payload ) { if( payload > curr.payload ) { prev = curr; curr = curr.next; } else { System.out.println( "ERROR" ); return; } } if( prev != null ) { prev.next = new Node2(curr,payload); } else { root = new Node2(curr,payload); } } }

^ what is that code?

how would i keep track of the previous node if there i did not declare a previous node in the node class and i don't think i am supposed to

no it has to be the custom linked list that i have so far. and what about the times method

public int compareTo(PolynomialTerm o)    {        if(this.exponent == o.exponent)        {            return 0;        }        else if(this.exponent < o.exponent)        {            return -1;        }        else        {            return 1;        }    }

the exception is line 17
here is the text
Exception in thread "main" java.lang.IllegalArgumentException: Term already exist
at LinkedPolynomial.insert(LinkedPolynomial.java:72)
at PolynomialTester.main(PolynomialTester.java:34)
/home/Surge/.cache/netbeans/8.2/executor-snippets/run.xml:53: Java returned: 1
BUILD FAILED (total time: 0 seconds)

i know im late  but here is my multiply/times method
public LinkedPolynomial times(LinkedPolynomial poly)    {        LinkedPolynomial poly1 = this;        LinkedPolynomial poly2 = new LinkedPolynomial();        PolynomialTerm term2;        Node term = poly.firstTerm;        Node term1 = poly1.firstTerm;        while(term1 != null)        {           term1 = term1.next;            while(term != null)            {                term2 = term.term.times(term1.term);                poly2.firstTerm = new Node(term2,poly2.firstTerm);                term = term.next;                            }          }        return poly2;    }

my insert method
public void insert(PolynomialTerm term)    {     LinkedPolynomial poly = this;        Node term1 = poly.firstTerm;        while(term1 != null)        {                if (term.compareTo(term1.term) == 1)                {                    term1 = new Node(term,term1);                }                    else if (term.compareTo(term1.term) == -1)                {                    term1 = term1.next;                }                    else                {                    throw new IllegalArgumentException("Term already exist");                }                }    }

my multiply method only multiplies one term of one polynomial with all the terms of the other polynomial nut it does not repeat the process with the other terms. my insert method thwos the exception no matter what term i try to insert. i really need help on these last two methods. the assignment is due TONIGHT and i also have the programming final tomorrow morning

after speaking with my professor the plus method is supposed to throw an exception but a polynomial exception if the exponents are not equal. for the ordering i will try something like the one in piet's node class and will get back to you. i still do not see why add(Polynomialterm pt) is necessary when i basically have that method in the polynomial term class. like is said before myy code is working just out of order

Would this be correct for the compareTo method
public int compareTo(PolynomialTerm o)    {                if(this.exponent == o.exponent)        {            return 0;        }        else if(this.exponent < o.exponent)        {            return -1;        }        else        {            return 1;        }          }

the only changes in my PT class were the adding of the exception(i haven't designed the polynomial exception yet) and the compareto method because i am not exactly sure how to implement it
public class PolynomialTerm implements Comparable<PolynomialTerm> {    private int exponent;    private int coefficient;        public PolynomialTerm(int exp, int coe)    {       this.exponent = exp;       this.coefficient = coe;          }    public int getExponent()    {        return exponent;    }    public int getCoefficient()    {        return coefficient;    }                    public int value(int x)    {        return (int) Math.pow(x,this.getExponent())*this.getCoefficient();    }        public PolynomialTerm plus(PolynomialTerm term )    {         PolynomialTerm term1;        if(term.getExponent() == this.getExponent())        {           term1 = new PolynomialTerm(this.getExponent(), (this.getCoefficient()+term.getCoefficient()));        }        else        {            throw new IllegalArgumentException();        }        return term1;     }        public PolynomialTerm times(PolynomialTerm term)    {        return new PolynomialTerm(term.getExponent()+this.getExponent(),term.getCoefficient()*this.getCoefficient());    }        public PolynomialTerm derivative()    {        PolynomialTerm term;        if (this.exponent == 0 )        {            term = new PolynomialTerm(0,0);        }        else        {            term = new PolynomialTerm(this.getExponent()-1,this.getExponent()*this.getCoefficient());        }                return term;    }    @Override    public String toString()    {        return "PolynomialTerm{" + coefficient+"x^"+ exponent + '}';    }    @Override    public int compareTo(PolynomialTerm o)    {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.    }

Here is my current code for the Polynomial(now LinkedPolynomial class)
public class LinkedPolynomial implements Comparable<PolynomialTerm> {       private class Node        {      PolynomialTerm term;      Node next;     public Node(PolynomialTerm term, Node n)      {         this.term = term;         this.next = n;      }    }        private Node firstTerm;      public LinkedPolynomial()    {        firstTerm = null;    }        public LinkedPolynomial(int[] data)    {        for(int i = 0; i < data.length-1; i+=2)        {            PolynomialTerm term = new PolynomialTerm(data[i],data[i+1]);            firstTerm = new Node(term,firstTerm) ;                    }              }        public LinkedPolynomial plus(LinkedPolynomial poly)    {       LinkedPolynomial poly1 = this;       LinkedPolynomial poly2 = new LinkedPolynomial();       PolynomialTerm term2;       Node term = poly.firstTerm;       Node term1 = poly1.firstTerm;         while(term != null && term1 != null)       {                             term2 = term1.term.plus(term.term);                             poly2.firstTerm = new Node(term2,poly2.firstTerm);              //poly2.firstTerm = poly.firstTerm.next;                term = term.next;                term1 = term1.next;       }       return poly2;    }    @Override    public String toString()    {       Node term = this.firstTerm;        String poly = "";        while(term != null)        {            switch (term.term.getExponent())            {                case 0:                    poly += term.term.getCoefficient() + " + ";                    break;                case 1:                    poly += term.term.getCoefficient() + "x" + "+";                    break;                default:                    poly += term.term.getCoefficient() + "x^" + term.term.getExponent() + " + ";                    break;            }          term = term.next;        }        return poly;    } }
it works but the terms are printed in opposite order. for instance if i just print out the polynomial with no operations done to it will print in the opposite order that it was inputed but after adding it to another polynomial it will print in the same order when it was inputed. what am i doing wrong?

Also, as i have said multiple times already i CANNOT, i repeat, CANNOT have another instance variable. my professor will not except it he is very strict about the way the assignment should done. For example in another assignment i had help from a tutor and the way the code was written was correct but that was not how he wanted it so i got a 76.

i use the same test code as the one from before. i use term.term.next because the first term refers to the node firstterm in the polynomial then the second term is the polynomial term referenced from the node class. Whats is an NPE?

when the polynomial class is the list itself the single variable requirement still stands so i cannot have a a head and tail variable only a head . in the code i posted above the problems seems to be with term.next when i remove the .next i get an ouput even if its incorrect but i think that is because of a tostring method that i created. Couk you show me what the t0string would look like?

you also said you understood what the requirement said regarding a single instance variable