[java] Problem With Algorithm

I have been working on a polynomial system in Java. I don't where it'll go, but it'll be useful to further projects. So this is how I planned it. You have a Monomial class which has a coefficient and a power of x, though more will be included eg: a differentiate function. Then you have a Polynomial class which has a vector which stores Monomial objects, herein the problem lies. When a Polynomial is made, I would like it to sort in descending powers of 'x', remove powers with coefficients of zero, and add coefficients of like powers. This last part does not work. I have redone the method 4 times and each time I get wrong results. Either this is an algorithmic problem or a problem in my head. The problems are in the "void sort()" method. The current method is very hard to follow because I got so frustrated while trying to make the method that I just stopped making neat, logical code and resort to messy code that has 1% chance of being written correctly. Monomial.java


class Monomial
{
 private long power = 0;
 private long coefficient = 0;
 
 public Monomial(long Power, long Coefficient)
 {
  power = Power;
  coefficient = Coefficient;
 }
 
 public String toString()
 {
  return "(" + coefficient + "x^" + power + ")"; 
 }
 
 public long getPower()
 {
  return power;
 }
 
 public void setPower(long newPower)
 {
  power = newPower;
 }
 
 public long getCoeff()
 {
  return coefficient;
 }
 
 public void setCoeff(long newCoefficient)
 {
  coefficient = newCoefficient;
 }
}

Polynomial.java


import java.util.*;

class Polynomial
{
 Vector monomials = new Vector();
 
 public Polynomial(Monomial terms[])
 {
  for(int i = 0; i < java.lang.reflect.Array.getLength(terms);i++)
   monomials.addElement(terms);
  
  sort();
 }
 
 public void sort()
 {  
  int difLength = 0;
  
  for(int i = 0; i < monomials.size(); i++)
  {
   boolean hasOccured = false;
   Monomial testObject = (Monomial) monomials.elementAt(i);
   
   for(int j = 0; j < i; j++)
   {
    Monomial currentObject = (Monomial) monomials.elementAt(j);
    if(currentObject.getPower() == testObject.getPower())
     hasOccured = true;
   }
   
   if(!hasOccured)
    difLength++;
  }
  
  if(difLength != monomials.size())
  {
   for(int i = 0; i < monomials.size(); i++)
   {
    Monomial testObject = (Monomial) monomials.elementAt(i);
    for(int j = 0; j < monomials.size(); j++)
    {
     Monomial currentObject = (Monomial) monomials.elementAt(j);
     if(currentObject.getPower() == testObject.getPower() /*&& (currentObject.equals(testObject))*/)
     {
      testObject.setCoeff(testObject.getCoeff() + currentObject.getCoeff());
      monomials.removeElementAt(j);
      j=0;
     }
    }
   }
   
   Monomial[] sortArray = new Monomial[difLength];
   
   for(int i = 0; 0 < monomials.size();i++)
   {
    long highestPower = ((Monomial) monomials.elementAt(0)).getPower();
    int num = 0; 
    for(int j = 0; j < monomials.size();j++)
    {
     Monomial currentObject = (Monomial) monomials.elementAt(j);
     highestPower = (highestPower > currentObject.getPower())? highestPower : currentObject.getPower();
     num = (highestPower > currentObject.getPower())? num : j;
    }
    
    sortArray = (Monomial) monomials.elementAt(num);
    monomials.removeElementAt(num);
   }
   
   for(int i = 0; i < difLength; i++)
    monomials.addElement(sortArray);
  }
  else
  {
   Monomial sortArray[] = new Monomial[monomials.size()];
   
   for(int i = 0; i < monomials.size(); i++)
   {
    sortArray = (Monomial) monomials.elementAt(i);
    monomials.removeElementAt(i);
   }
   
   for(int i = 0; i < monomials.size(); i++)
   {
    long highestPower = ((Monomial) monomials.elementAt(0)).getPower();
    int num = 0;
     
    for(int j = 0; j < monomials.size(); j++)
    {
     Monomial currentObject = (Monomial) monomials.elementAt(j);
     highestPower = (highestPower > currentObject.getPower()) && !(monomials.contains(currentObject))? highestPower : currentObject.getPower();
     num = (highestPower > currentObject.getPower())  && !(monomials.contains(currentObject))? num : j;
    }
    
    sortArray = (Monomial) monomials.elementAt(num);
    monomials.removeElementAt(num);
   }
  }
 }
 
 public String toString()
 {
  String s = "";
  
  for(int i = 0; i < monomials.size();i++)
   s = s + monomials.elementAt(i).toString();
   
  return s;
 }
}

TestPolynomial.java


class TestPolynomial
{
 public static void main(String args[])
 {
  Monomial[] m = new Monomial[5];
  
  for(int i = 0; i < 5; i++)
  {
   long Power = (long) Math.round(Math.random() * 10);
   long Coeff = (long) Math.round(Math.random() * 10);
    
   m = new Monomial(Power, Coeff);
  }
  
  Polynomial p = new Polynomial(m);
  
  for(int i = 0; i < 5; i++)
   System.out.println(m);
   
  System.out.println(); 
  System.out.println(p.toString());
 }
}

Thank you.

if(difLength != monomials.size()) { for(int i = 0; i < monomials.size(); i++) { Monomial testObject = (Monomial) monomials.elementAt(i); for(int j = 0; j < monomials.size(); j++) { Monomial currentObject = (Monomial) monomials.elementAt(j); if(currentObject.getPower() == testObject.getPower() /*&& (currentObject.equals(testObject))*/) { testObject.setCoeff(testObject.getCoeff() + currentObject.getCoeff()); monomials.removeElementAt(j); j=0; } } }

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