polynomial.java

该程序实现两个一元多项式表达式的输入

package me;

import java.util.LinkedList;
import java.util.ListIterator;

class Polynomial{
    Polynomial(){
        linkList=new LinkedList<Term>();
    }
    Polynomial(LinkedList<Term> linkList){
        this.linkList=linkList;
    }
    void addTerm(Term term){
        
        ListIterator<Term> it=linkList.listIterator();
        if(linkList.isEmpty()){
            linkList.addFirst(term);
            return ;
        }
        while(it.hasNext()){
            Term t=it.next();
            if(term.compareTo(t)<0){
                it.previous();
                it.add(term);
                return;
            } else if(term.compareTo(t)==0){
                if(t.getCoef()+term.getCoef()==0){
                    it.remove();
                    return;
                } else{
                    it.set(new Term((t.getCoef()+term.getCoef()),t.getExpn()));
                    return;
                }
                
            }
        }
        it.add(term);
    }
    
    private void subtractTerm(Term t){
        t.setCoef(-t.getCoef());
        addTerm(t);
    }
    
    private void multiplyTerm(Term t){
        ListIterator<Term> it=linkList.listIterator();
        while(it.hasNext()){
            Term term=it.next();
            float c=term.getCoef()*t.getCoef();
            int e=term.getExpn()+t.getExpn();
            it.set(new Term(c,e));
        }
    }
    public Polynomial clone(){
        LinkedList<Term> l=new LinkedList();
        ListIterator<Term> it=linkList.listIterator();
        while(it.hasNext()){
            Term t=new Term(it.next());
            l.add(t);
        }
        return new Polynomial(l);
    }
    void addPoly(Polynomial p){
        ListIterator<Term> it=p.getLinkList().listIterator();
        while(it.hasNext()){
            addTerm(it.next());
        }
    }
    void subtractPolyn(Polynomial p){
        ListIterator<Term> it=p.getLinkList().listIterator();
        while(it.hasNext()){
            subtractTerm(it.next());
        }
    }
    void multiplyPolyn(Polynomial p){
        ListIterator<Term> it=p.getLinkList().listIterator();
        Polynomial temp=new Polynomial();;
        while(it.hasNext()){
            Polynomial px=this.clone();
            px.multiplyTerm(it.next());
            temp.addPoly(px);
        }
        linkList=temp.getLinkList();
    }
    LinkedList getLinkList(){
        return linkList;
    }
    private LinkedList<Term> linkList;
}