diff options
| -rw-r--r-- | Week7/src/polynomial/Polynomial.java | 65 | ||||
| -rw-r--r-- | Week7/src/polynomial/Term.java | 10 | ||||
| -rw-r--r-- | Week7/test/polynomial/PolynomialTest.java | 22 |
3 files changed, 66 insertions, 31 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) diff --git a/Week7/src/polynomial/Term.java b/Week7/src/polynomial/Term.java index b8d9f16..7cde927 100644 --- a/Week7/src/polynomial/Term.java +++ b/Week7/src/polynomial/Term.java @@ -8,6 +8,9 @@ import java.util.Scanner; * @author Sjaak Smetsers * @version 1.0 * @date 15-02-2012 + * + * @author Camil Staps, s4498062 + * @date 17-03-2015 */ public class Term { @@ -94,6 +97,8 @@ public class Term { /** * Standard implementation of equality + * @param may_be_term the object to check equality with + * @return true iff may_be_term represents the same term as this term */ @Override public boolean equals(Object may_be_term) { @@ -106,6 +111,11 @@ public class Term { } } + /** + * Apply a term to a concrete variable + * @param x the variable to apply the term to + * @return the result of the application of the term to x + */ public double apply(double x) { return coefficient * Math.pow(x, exponent); } diff --git a/Week7/test/polynomial/PolynomialTest.java b/Week7/test/polynomial/PolynomialTest.java index dc31900..7d7275a 100644 --- a/Week7/test/polynomial/PolynomialTest.java +++ b/Week7/test/polynomial/PolynomialTest.java @@ -5,7 +5,6 @@ */ package polynomial; -import java.util.Scanner; import org.junit.After; import org.junit.AfterClass; import org.junit.Before; @@ -14,8 +13,8 @@ import org.junit.Test; import static org.junit.Assert.*; /** - * - * @author camilstaps + * A test class for the polynomial.Polynomial class + * @author Camil Staps, s4498062 */ public class PolynomialTest { @@ -113,23 +112,6 @@ public class PolynomialTest { } /** - * Test of plus method, of class Polynomial. - */ - @Test - public void testPlus_Term() { - System.out.println("plus"); - Term t = Term.scanTerm(new Scanner("5 3")); - - Polynomial instance = new Polynomial("4 7 2 3 1 0"); // normal addition - instance.plus(t); - assertEquals(new Polynomial("4 7 7 3 1 0"), instance); - - instance = new Polynomial("4 7 -5 3 1 0"); // addition when the term cancels out - instance.plus(t); - assertEquals(new Polynomial("4 7 1 0"), instance); - } - - /** * Test of apply method, of class Polynomial. */ @Test |