Thread: multiplication of polynomials method functionality

Hello i am trying to work out how to multiply two polynomials entered from keyboard input together. Have got the addition working, and multiplying by a constant. But am unable to get the multiplication method and functionality right.
You can see my attempt at multiplication under multiply by a monomial code.

Any help is appreciated.

thanks

 
import java.util.*;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.text.*;
import java.io.IOException;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Scanner;
 
 
public class Polynomial
{
   private Monomial head;
   private int TOLERANCE = 0;
 
 
 
 
 
/******************  the  Monomial (inner) class   ********************************/
 
   private class Monomial
   {
      private DecimalFormat precision = new DecimalFormat("#.####");
      private int deg;     // degree of polynomial
      private int coeff; // coefficients
      private Monomial next; // Pointer to next term
 
 
      public Monomial(int coeff, int deg, Monomial next)
      {
         this.coeff = coeff;  	//coefficient
         this.deg = deg;  		// Degree
         this.next = next;		// Pointer
      }
      public String toString()
      {
         String form = precision.format(Math.abs(coeff));
 
         if(deg == 0) return form ;
         else
         if(deg == 1) return form + "x";
         else
         return form +"x^" + deg;
      }
      public boolean equals(Monomial mono)
      {
         return coeff == mono.coeff && deg == mono.deg;
      }
 
   }
 
//*********************************************************************************************
 
   public Polynomial()
   {
      head = null;
   }
 
 /***************************************************************************
   *  Adds a new term into the polynomial, assuming that the polynomial
   *  is sorted in order from smallest to largest exponent.
 **************************************************************************/
   public void addTerm(int coeff, int deg)
   {
      if( Math.abs(coeff) < TOLERANCE ) return;
 
      if( head == null || deg < head.deg )
      {
         head = new Monomial(coeff, deg, head);
         return;
      }
 
      Monomial cur = head;
      Monomial prev = null;
 
      while( cur != null && deg > cur.deg)
      {
         prev = cur;
         cur = cur.next;
      }
      if( cur == null || deg != cur.deg )
			prev.next = new Monomial(coeff, deg, cur);
      else
      {
         cur.coeff += coeff;
         if( Math.abs(cur.coeff) < TOLERANCE )
           if(prev != null)
               prev.next = cur.next;
            else
               head = head.next;
      }
   }
 
   public String toString()
   {
      StringBuffer sb = new StringBuffer();
 
      for(Monomial tmp = head; tmp != null; tmp = tmp.next)
        if(tmp.coeff < 0 )
           sb.append(" - " + tmp.toString());
        else
           sb.append(" + " + tmp.toString());
 
      return sb.toString();
   }
 
//*********************************************************************************************
 
 
/*********************************************************************************************
 
   *  Return the degree of this polynomial
 
 **********************************************************************************************/
 
 
 
//*********************************************************************************************/
 
 
 
/*********************************************************************************************
   *  Multiplies Polynomial 1 to Polynomial 2
   *  The method does not change the original polynomial.
**********************************************************************************************/
 
 
 
 
 
//*********************************************************************************************/
 
/*********************************************************************************************
   *  Adds Polynomial 1 to Polynomial 2
   *  The method does not change the original polynomial.
**********************************************************************************************/
   public Polynomial add(Polynomial poly)
   {
      Polynomial res = clone();
 
      for(Monomial tmp = poly.head; tmp != null; tmp = tmp.next)
         res.addTerm(tmp.coeff, tmp.deg);
 
      return res;
   }
 
   public Polynomial clone()
   {
      Polynomial res = new Polynomial();
 
      for(Monomial tmp = head; tmp != null; tmp = tmp.next)
         res.addTerm(tmp.coeff, tmp.deg);
 
      return res;
   }
 
   public boolean equals(Polynomial poly)
   {
      Monomial tmp1 = head;
      Monomial tmp2 = poly.head;
 
      while(tmp1 != null && tmp2 != null)
      {
         if( !tmp1.equals(tmp2) ) return false;
         tmp1 = tmp1.next;
         tmp2 = tmp2.next;
      }
      return true;
   }
 
//*********************************************************************************************/
 
 
/*********************************************************************************************
   *  Multiplies by a Constant
   *  The method does not change the original polynomial.
**********************************************************************************************/
 
   public Polynomial multiply(int num)
   {
      Polynomial res = clone();
 
      for(Monomial tmp = res.head; tmp != null; tmp = tmp.next)
         tmp.coeff *= num;
 
      return res;
   }
 
//*********************************************************************************************/
 
 
 /*********************************************************************************************
   *  Returns a new polynomial that is the derivative of this polynomial.
 **********************************************************************************************/
   public Polynomial diff()
   {
      Polynomial res = new Polynomial();
 
      for(Monomial tmp = head; tmp != null; tmp = tmp.next)
      {
         if(tmp.deg != 0)
            res.addTerm(tmp.coeff * tmp.deg, tmp.deg - 1 );
      }
 
      return res;
   }
 
//*********************************************************************************************/
 
 
 /*********************************************************************************************
   *  Returns a new polynomial that is the result of Monomial times polynomial.
   **  The method does not change the original polynomial.
 **********************************************************************************************/
/*
public Polynomial times(Polynomial poly)
   {
          {
      Polynomial result = new Polynomial();
 
 
 
         for(Monomial tmp2 = poly.head; tmp2 != null; tmp2 = tmp2.next)
         res.addTerm(tmp2.coeff, tmp2.deg );
 
 
         for(Monomial tmp = head; tmp != null; tmp = tmp.next)
         res.addTerm(tmp.coeff, tmp.deg);
 
      while(tmp != null && tmp2 != null)
      {
         result.addTerm(tmp.coeff * tmp2.coeff, tmp.deg + tmp2.deg);
         tmp = tmp.next;
         tmp2 = tmp2.next;
      }
      return result;
 
 
   }
 
   }
*/
 
 
 
 
 
//*********************************************************************************************/
 
 
 
 
 /*********************************************************************************************
   *  Driver Program to Test Polynomial Class
 **********************************************************************************************/
 
   public static void main(String[] args)
 
   {
 
//---------------- Code to chose between keyboard input or file input------------------------
 
 
	  System.out.println("If you would like you enter the polynomial via a text file 'Polyinput.txt' PRESS 
 
1. ");
	  System.out.println("If you would like you enter the polynomial via the keyboard, PRESS ANY OTHER 
 
INTEGER... ");
      Scanner inputquestion=new Scanner(System.in);
      System.out.print("Enter Option: "); // Prompts for selection choice
      int option=inputquestion.nextInt(); // Stores input in option
 
		if (option == 1) // if loop to jump into read from text file
		{
 
 
 
//--------------  Read Input from File.------------------------------------------------------------
 
 
        String content = new String();
		String name = new String();
		File file = new File("polyinput.txt");
		LinkedList<String> list = new LinkedList<String>();
 
		try {
			Scanner sc = new Scanner(new FileInputStream(file));
				while (sc.hasNext()) {
				name = sc.next();
				content = sc.nextLine();
				list.add(content);
 
			}
 
			sc.close();
		} catch (FileNotFoundException fnfe) {
			fnfe.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
			System.out.println("\nProgram terminated Safely...");
		}
 
		Iterator<String> i = list.iterator();
		while (i.hasNext()) {
			System.out.println(name + i.next() + "\n");
 
		}
 
 
	} //------------ End if to enter input text file code---------------------------------------
 
 
 
 
	else  //--------------start of else for keyboard input--------------------------------------
	{
 
	//------- Code to Prompt for Polynomial 1 
 
-----------------------------------------------------------------
 
 
	  Polynomial polynomial1 = new Polynomial();
	  System.out.println( );
	  System.out.println( );
	  System.out.println("Enter first Polynomial");
	  System.out.println("(Enter Zero (0) as Exponent value to move to second Polynomial");
	  System.out.println( );
 
	  //Insert do while loop exponent not equal 0
	 int ExponentTest = 1;
	  do {
 
      Scanner inputCoefficent=new Scanner(System.in);
      System.out.print("Enter Coefficient: "); // Prompts for coefficent
      int Coefficient=inputCoefficent.nextInt(); // Stores coefficent in coefficent
      Scanner inputExponent=new Scanner(System.in);
      System.out.print("Enter Exponent: "); // Prompts for Exponent
      int Exponent=inputExponent.nextInt(); // Stores Exponent in Exponent
 
        if (Exponent < 1)
          {
          	ExponentTest = 0;
          }
 
 
      polynomial1.addTerm(Coefficient, Exponent);
 
       } while (ExponentTest > 0);
        // ------ end do while loop ---------------
 
      System.out.println( );
      System.out.println( " Entered Polynomial is: " + polynomial1 );
 
 
//----------------------------------------------------------------------------------------------------------
 
//----------- Code to Prompt for Polynomial 2 -----------------------------------------------------------------
 
	  Polynomial polynomial2 = new Polynomial();
	  System.out.println( );
	  System.out.println( );
	  System.out.println("Enter second Polynomial");
	  System.out.println("(Enter Zero (0) as Exponent value to complete Polynomial");
	  System.out.println( );
 
	  //Insert do while loop exponent not equal 0
	 int ExponentTest2 = 1;
	  do {
 
      Scanner inputCoefficent=new Scanner(System.in);
      System.out.print("Enter Coefficient: "); // Prompts for coefficent
      int Coefficient=inputCoefficent.nextInt(); // Stores coefficent in coefficent
      Scanner inputExponent=new Scanner(System.in);
      System.out.print("Enter Exponent: "); // Prompts for Exponent
      int Exponent=inputExponent.nextInt(); // Stores Exponent in Exponent
 
        if (Exponent < 1)
          {
          	ExponentTest2 = 0;
          }
 
 
      polynomial2.addTerm(Coefficient, Exponent);
 
       } while (ExponentTest2 > 0);
        // ------ end do while loop ---------------
 
      System.out.println( );
      System.out.println( " Entered Polynomial is: " + polynomial2 );
 
//----------------------------------------------------------------------------------------------------------
 
 
//------- Code to Prompt for Monomial (ax^k) to multiply both Polynomials by---------------------------------
 
	  Polynomial monomial1 = new Polynomial();
	  System.out.println( );
	  System.out.println( );
	  System.out.println("Enter details for the Monomial equation");
      Scanner inputMonomial=new Scanner(System.in);
            System.out.print("Enter Coefficent: "); //Prompts for Coefficient
            int num1=inputMonomial.nextInt(); // Stores Coefficient in num1
            System.out.print("Enter Exponent: "); // Prompts for Exponent
            int num2=inputMonomial.nextInt(); //Stores Exponenent in num2
            monomial1.addTerm(num1, num2); // Creates the Monomial equation
 
        System.out.println();
        System.out.println( "Monomial: " );
	    System.out.println( monomial1 );
        System.out.println( );
 
//----------------------------------------------------------------------------------------------------
 
//------- Code to Prompt for constant to multiply by and then reads in the constant and stores in Constant1
 
   	  System.out.println("Enter integer to be used as the constant");
      Scanner inputConstant=new Scanner(System.in);
      System.out.print("Enter Constant: "); // Prompts for constant
      int Constant1=inputConstant.nextInt(); // Stores Constant in Constant1
 
      System.out.println( "Constant used to multiply polynomials: " );
	  System.out.println( Constant1 );
      System.out.println( );
 
//----------------------------------------------------------------------------------------------------------
 
 
//------------------------ Returns display for operations onto the screen-----------------------------------
 
 
	  System.out.println( );
      System.out.println( "Degree of Polynomial 1 ("+ polynomial1 + "): " /*+ polynomial1.degree()*/);
 
 
      System.out.println( );
      System.out.println( "Degree of Polynomial 2 ("+ polynomial2 + "): " );
 
      System.out.println( );
      System.out.println( "Multiply Polynomial 1 ("+ polynomial1 + ") by Polynomial 2 ("+ polynomial2 + "): " );
 
      System.out.println( );
      System.out.println( "Multiply Polynomial 1 ("+ polynomial1 + ") by Monomial ("+ monomial1 + "): " );
      Polynomial MultiplyMonomialResult1 = polynomial1.add(monomial1);
      System.out.println( monomial1 + " * " + polynomial1 + " = " + MultiplyMonomialResult1 );
      System.out.println( );
 
      System.out.println( );
      System.out.println( "Multiply Polynomial 2 ("+ polynomial2 + ") by Monomial ("+ monomial1 + "): " );
      Polynomial MultiplyMonomialResult2 = polynomial2.add(monomial1);
      System.out.println( monomial1 + " * " + polynomial2 + " = " + MultiplyMonomialResult2 );
      System.out.println( );
 
      System.out.println( );
      System.out.println( "Polynomial 1 (" + polynomial1 + ") plus Polynomial 2 (" + polynomial2 + "): " );
      Polynomial AdditionResult = polynomial1.add(polynomial2);
      System.out.println( polynomial1 );
      System.out.println( polynomial2 );
      System.out.println( "=" );
      System.out.println( AdditionResult );
      System.out.println( );
 
      System.out.println( "multiply Polynomial 1 ("+ polynomial1 + ") by constant entered into console (ie " + 
 
Constant1 + "): " );
      Polynomial MultiplyConstant1 = polynomial1.multiply(Constant1);
      System.out.println( Constant1 + " * " + polynomial1 + " = " + MultiplyConstant1 );
      System.out.println( );
 
      System.out.println( "multiply Polynomial 2 ("+ polynomial2 + ") by constant entered into console (ie " + 
 
Constant1 + "): " );
      Polynomial MultiplyConstant2 = polynomial2.multiply(Constant1);
      System.out.println( Constant1 + " * " + polynomial2 + " = " + MultiplyConstant2 );
      System.out.println( );
 
      System.out.println( "Derivative of Polynomial 1: " );
      Polynomial diffresult1 = polynomial1.diff();
      System.out.println( "Polynomial 1: " + polynomial1 );
      System.out.println( "Derivative =  " + diffresult1 );
      System.out.println( );
 
      System.out.println( "Derivative of Polynomial 2" );
      Polynomial diffresult2 = polynomial2.diff();
      System.out.println( "Polynomial 2: " + polynomial2 );
      System.out.println( "Derivative =  " + diffresult2 );
      System.out.println( );
 
//-------------------------------End Screen output of operations for keyboard entry-------------------------
 
} // End of else for keyboard input.------------------------------------------------------------------------
 
 
   }
}

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