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package polynomial;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Scanner;
/**
* A skeleton class for representing Polynomials
*
* @author Sjaak Smetsers
* @date 10-03-2015
*/
public class Polynomial {
/**
* A polynomial is a sequence of terms here kept in an List
*/
List<Term> terms;
/**
* A constructor for creating the zero Polynomial zero is presented as an
* empty list of terms and not as a single term with 0 as a coefficient
*/
public Polynomial() {
terms = new ArrayList<>();
}
/**
* A Constructor creating a polynomial from the argument string.
*
* @param s a String representing a list of terms which is converted to a
* scanner and passed to scanTerm for reading each individual term
*/
public Polynomial( String s ) {
terms = new ArrayList<>();
Scanner scan = new Scanner(s);
for (Term t = Term.scanTerm(scan); t != null; t = Term.scanTerm(scan)) {
terms.add(t);
}
}
/**
* The copy constructor for making a deep copy
*
* @param p the copied polynomial
*
*/
public Polynomial( Polynomial p ) {
terms = new ArrayList<>(p.terms.size());
for (Term t : p.terms) {
terms.add(new Term(t));
}
}
/**
* A straightforward conversion of a Polynomial into a string based on the
* toString for terms
*
* @return a readable string representation of this
*/
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
boolean not_first = false;
for (Term t : terms) {
if (not_first && t.getCoef() >= 0)
sb.append("+");
sb.append(t);
not_first = true;
}
return sb.toString();
}
public void plus(Polynomial b) {
for (Term t : b.terms)
plus(t);
}
public void plus(Term t) {
Iterator<Term> iter = terms.iterator();
while (iter.hasNext()) {
Term this_t = iter.next();
if (this_t.getExp() == t.getExp()) {
this_t.plus(t);
if (this_t.getCoef() == 0)
iter.remove();
return;
}
}
terms.add(t);
}
public void minus(Polynomial b) {
b.times(new Polynomial("-1 0"));
plus(b);
}
public void times(Polynomial b) {
Polynomial result = new Polynomial();
for (Term that_t : b.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;
}
public void divide(Polynomial b) {
}
@Override
public boolean equals(Object other_poly) {
Polynomial that = (Polynomial) other_poly;
if (terms.size() != that.terms.size())
return false;
for (Term this_t : terms) {
Iterator<Term> that_iter = that.terms.iterator();
boolean found = false;
while (that_iter.hasNext()) {
if (this_t.equals(that_iter.next())) {
found = true;
that_iter.remove();
break;
}
}
if (!found) {
return false;
}
}
return true;
}
public double apply(double x) {
double result = 0;
for (Term t : terms)
result += t.apply(x);
return result;
}
}
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