---

#include <iostream>
using namespace std;

// Базовый класс (полином 2 степени)
class Polynomial2 {
protected:
    double* coef; // указатель на массив коэффициентов

public:
    // Конструктор без параметров
    Polynomial2() {
        coef = new double[3]; // 3 коэффициента
        for (int i = 0; i < 3; i++)
            coef[i] = 0;
    }

    // Конструктор с параметрами
    Polynomial2(double a0, double a1, double a2) {
        coef = new double[3];
        coef[0] = a0;
        coef[1] = a1;
        coef[2] = a2;
    }

    // Конструктор копирования
    Polynomial2(const Polynomial2& other) {
        coef = new double[3];
        for (int i = 0; i < 3; i++)
            coef[i] = other.coef[i];
    }

    // Деструктор
    ~Polynomial2() {
        delete[] coef;
    }

    // Оператор присваивания
    Polynomial2& operator=(const Polynomial2& other) {
        if (this != &other) {
            for (int i = 0; i < 3; i++)
                coef[i] = other.coef[i];
        }
        return *this;
    }

    // Сумма коэффициентов
    double sum() const {
        return coef[0] + coef[1] + coef[2];
    }

    // Вывод
    virtual void print() const {
        cout << coef[2] << "x^2 + "
             << coef[1] << "x + "
             << coef[0] << endl;
    }

    // Оператор []
    double& operator[](int index) {
        return coef[index];
    }

    const double& operator[](int index) const {
        return coef[index];
    }

    // Оператор +
    Polynomial2 operator+(const Polynomial2& other) const {
        return Polynomial2(
            coef[0] + other.coef[0],
            coef[1] + other.coef[1],
            coef[2] + other.coef[2]
        );
    }
};

// Производный класс (полином 3 степени)
class Polynomial3 : public Polynomial2 {
public:
    // Конструктор без параметров
    Polynomial3() {
        delete[] coef;
        coef = new double[4];
        for (int i = 0; i < 4; i++)
            coef[i] = 0;
    }

    // Конструктор с параметрами
    Polynomial3(double a0, double a1, double a2, double a3) {
        coef = new double[4];
        coef[0] = a0;
        coef[1] = a1;
        coef[2] = a2;
        coef[3] = a3;
    }

    // Конструктор копирования
    Polynomial3(const Polynomial3& other) {
        coef = new double[4];
        for (int i = 0; i < 4; i++)
            coef[i] = other.coef[i];
    }

    // Деструктор
    ~Polynomial3() {
        delete[] coef;
    }

    // Оператор присваивания
    Polynomial3& operator=(const Polynomial3& other) {
        if (this != &other) {
            for (int i = 0; i < 4; i++)
                coef[i] = other.coef[i];
        }
        return *this;
    }

    // Сумма коэффициентов
    double sum() const {
        return coef[0] + coef[1] + coef[2] + coef[3];
    }

    // Переопределение print
    void print() const override {
        cout << coef[3] << "x^3 + "
             << coef[2] << "x^2 + "
             << coef[1] << "x + "
             << coef[0] << endl;
    }

    // Оператор []
    double& operator[](int index) {
        return coef[index];
    }

    const double& operator[](int index) const {
        return coef[index];
    }

    // Оператор +
    Polynomial3 operator+(const Polynomial3& other) const {
        return Polynomial3(
            coef[0] + other.coef[0],
            coef[1] + other.coef[1],
            coef[2] + other.coef[2],
            coef[3] + other.coef[3]
        );
    }
};

// Тестовая программа
int main() {
    Polynomial3 p1(1, 2, 3, 4);
    Polynomial3 p2(5, 6, 7, 8);

    Polynomial3 p3 = p1 + p2;

    p1.print();
    p2.print();
    p3.print();

    cout << "Sum p3 = " << p3.sum() << endl;

    p3[0] = 100;
    p3.print();

    return 0;
}