Namolem

/*
    Многочлен P(x)=anxn + an-1xn-1 +...+ a1x + a0 с целыми коэффициентами можно представить в виде списка,
    причем если ai=0, то соответствующее звено не включать в список. Определить процедуру, которая строит
    многочлен p – произведение многочленов q и r.
*/
#include <iostream>
#include <cmath>
#include <cstdlib>
#include <ctime>
using namespace std;

class Element
{
public:
    unsigned int num;
    double a;
    Element *nextElement;

    Element()
    {
        a = 0;
        num = 0;
        nextElement = NULL;
    }
    Element(int newNum,double newA)
    {
        a = newA;
        num = newNum;
        nextElement = NULL;
    }
    Element(const Element* copyElement)
    {
        a = copyElement->a;
        num = copyElement->num;
        nextElement = copyElement->nextElement;
    }
};

class PolinomList
{
    Element *firstElement;
    Element *lastElement;
    unsigned int size;
    unsigned int degree;

public:
    PolinomList();
    PolinomList(Element *firstElement);
    ~PolinomList();

    bool isBlank();
    void addElement(Element *newElement);
    void addElement(int newNum,double newA);

    double calculatePolinom(double x);
    void printElements();
    double getKoeffitientByNum(int reqNum);
    PolinomList operator*(PolinomList second);

};


PolinomList::PolinomList()
{
    firstElement = lastElement = NULL;
    size = 0;
    degree = 0;
}
PolinomList::PolinomList(Element *newfirstElement)
{
    firstElement = lastElement = new Element(newfirstElement);
    size = 1;
    degree = firstElement->num;
}
PolinomList::~PolinomList()
{
    Element *currentElement = firstElement;
    Element *tempElement;
    while (currentElement != lastElement && currentElement != NULL)
    {
        tempElement = currentElement;
        currentElement = currentElement->nextElement;
        delete tempElement;
    }
    delete currentElement;
}
bool PolinomList::isBlank()
{
    return (size)?  true : false;
}
void PolinomList::addElement(Element *newElement)
{
    addElement(newElement->num,newElement->a);
}
void PolinomList::addElement(int newNum,double newA)
{
    Element *newElement = new Element(newNum,newA);
    if (firstElement == NULL)
    {
        firstElement = lastElement = newElement;
    }
    else
    {
        lastElement->nextElement = newElement;
        lastElement = newElement;
    }
    size++;
    if (lastElement->num > degree) degree = lastElement->num;
}
double PolinomList::calculatePolinom(double x)
{
    Element *currentElement = firstElement;
    double result = 0;
    if (currentElement == NULL)
        return 0;
    do
    {
        result += pow(x,(double)currentElement->num)*currentElement->a;
        currentElement = currentElement->nextElement;
    }
    while (currentElement!=lastElement);

    return result;
}
void PolinomList::printElements()
{
    Element *currentElement = firstElement;
    if (currentElement == NULL)
    {
        cout <<"Попытка напечатать пустой список\n";
        return;
    }

    do
    {
        if (currentElement->a != 0)
            cout <<"("<<currentElement->num<<","<<currentElement->a<<") ";
        currentElement = currentElement->nextElement;
    }
    while (currentElement!=lastElement);
    cout <<endl;
}
double PolinomList::getKoeffitientByNum(int reqNum)
{
    Element *currentElement = firstElement;

    do
    {
        if (currentElement == NULL) return 0;
        if (currentElement->num == reqNum)
            return currentElement->a;
        currentElement = currentElement->nextElement;
    }
    while (currentElement != lastElement);
    return 0;
}
PolinomList PolinomList::operator*(PolinomList second)
{
    unsigned int newDegree = this->degree+second.degree;
    double *newKoeffitients = new double[newDegree];
    PolinomList resultPolinom;

    for (unsigned int i = 0;i<newDegree;i++)
        newKoeffitients[i] = 0;
    for (unsigned int i = 0;i<this->degree;i++)
        for (unsigned int j = 0;j<second.degree;j++)
            newKoeffitients[i+j] += this->getKoeffitientByNum(i) * second.getKoeffitientByNum(j);
    for (unsigned int i = 0;i<newDegree;i++)
    {
        if (newKoeffitients[i] != 0)
            resultPolinom.addElement(i,newKoeffitients[i]);
    }
    return resultPolinom;
}


int main()
{
    srand(time(NULL));
    PolinomList q,r,p;
    for (int i = 0;i<7;i++)
    {
        double a;
        a = (rand()%5 <2)?  0 : rand()%20;
        q.addElement(i,a);

        a = (rand()%5 <2)?  0 : rand()%20;
        r.addElement(i,a);

    }
    cout <<"Q: "; q.printElements();
    cout <<"R: "; r.printElements();

    p = q*r;
    cout <<"Q*R: "; p.printElements();
    //system("pause");

    return 0;
}