1 files changed, 54 insertions, 11 deletions

diff --git a/Week7/src/polynomial/Polynomial.java b/Week7/src/polynomial/Polynomial.java
index 2a1b28e..40c1448 100644
--- a/Week7/src/polynomial/Polynomial.java
+++ b/Week7/src/polynomial/Polynomial.java
@@ -6,10 +6,13 @@ import java.util.List;
 import java.util.Scanner;
 
 /**
- * A skeleton class for representing Polynomials
+ * A class for representing Polynomials
  *
  * @author Sjaak Smetsers
  * @date 10-03-2015
+ * 
+ * @author Camil Staps, s4498062
+ * @date 17-03-2015
  */
 public class Polynomial {
 
@@ -28,6 +31,18 @@ public class Polynomial {
 
     /**
      * A Constructor creating a polynomial from the argument string.
+     * 
+     * This implementation, in contrast to the given implementation, allows for 
+     * entering polynomials with two or more terms with the same exponent. Even 
+     * though this is strictly not necessary and these inputs aren't legit, this
+     * behaviour is always better than the behaviour of the given implementation 
+     * which would happily add two terms with the same exponent to our list.
+     * 
+     * This implementation also directly checks that the coefficient unequals 0,
+     * which is also not need-to-have, but still nice-to-have.
+     * 
+     * Both changes to the given implementation do not change the behaviour on
+     * legit input but do allow a user to mess up in some cases.
      *
      * @param s a String representing a list of terms which is converted to a
      * scanner and passed to scanTerm for reading each individual term
@@ -36,16 +51,15 @@ public class Polynomial {
         terms = new ArrayList<>();
         Scanner scan = new Scanner(s);
 
-        for (Term t = Term.scanTerm(scan); t != null; t = Term.scanTerm(scan)) {
-            terms.add(t);
-        }
+        for (Term t = Term.scanTerm(scan); t != null; t = Term.scanTerm(scan))
+            if (t.getCoef() != 0)
+                plus(t);
     }
 
     /**
      * The copy constructor for making a deep copy
      *
      * @param p the copied polynomial
-     *
      */
     public Polynomial( Polynomial p ) {
         terms = new ArrayList<>(p.terms.size());
@@ -73,12 +87,20 @@ public class Polynomial {
         return sb.toString();
     }
 
+    /**
+     * Add a polynomial to this polynomial
+     * @param b the polynomial to add
+     */
     public void plus(Polynomial b) {
         for (Term t : b.terms)
             plus(t);
     }
     
-    public void plus(Term t) {
+    /**
+     * Add a term
+     * @param t the term to add
+     */
+    private void plus(Term t) {
         Iterator<Term> iter = terms.iterator();
         while (iter.hasNext()) {
             Term this_t = iter.next();
@@ -92,14 +114,22 @@ public class Polynomial {
         terms.add(t);
     }
 
-    public void minus(Polynomial b) {
-        b.times(new Polynomial("-1 0"));
-        plus(b);
+    /**
+     * Subtract a polynomial from this polynomial
+     * @param p the polynomial to subtract
+     */
+    public void minus(Polynomial p) {
+        p.times(new Polynomial("-1 0"));
+        plus(p);
     }
 
-    public void times(Polynomial b) {
+    /**
+     * Multiply a polynomial with this polynomial
+     * @param p the polynomial to multiply with
+     */
+    public void times(Polynomial p) {
         Polynomial result = new Polynomial();
-        for (Term that_t : b.terms) 
+        for (Term that_t : p.terms) 
             for (Term this_t : terms)
                 result.plus(new Polynomial((that_t.getCoef() * this_t.getCoef()) + " " + (that_t.getExp() + this_t.getExp())));
         terms = result.terms;
@@ -108,8 +138,16 @@ public class Polynomial {
     public void divide(Polynomial b) {
     }
 
+    /**
+     * Check equality
+     * @param other_poly the object to check with
+     * @return true iff other_poly this instance
+     */
     @Override
     public boolean equals(Object other_poly) {
+        if (other_poly == null || other_poly.getClass() != getClass())
+            return false;
+        
         Polynomial that = (Polynomial) other_poly;
         if (terms.size() != that.terms.size()) 
             return false;
@@ -130,6 +168,11 @@ public class Polynomial {
         return true;
     }
     
+    /**
+     * Apply the polynomial to a concrete variable
+     * @param x the variable
+     * @return the result of the polynomial applied on x
+     */
     public double apply(double x) {
         double result = 0;
         for (Term t : terms)