// I just need codes for an assignment operator ("="), and a destructor working with the main() and the class Polynomial that I am providing below.. Thanks in advance..

#include

#include

#include

using namespace std;

struct Node{

int data;

Node *next;

};

Node* newNode(int data){

Node* node = new Node();

node->data = data;

node->next = NULL;

return node;

}

class Polynomial{

private:

Node* head;

int space;

public:

Polynomial(){

head = newNode(0);

}

Polynomial(initializer_list c){

initializer_list::iterator it;

initializer_list::iterator last;

last = c.end()-1;

head = newNode(int(*last));

Node* temp = head;

if(c.size() >= 2){

for ( it=c.end()-2; ; it--){

Node* node = newNode(int(*it));

temp->next = node;

temp = node;

space++;

if(it == c.begin()){

break;

}

}

}

}

int getspace()const{

return space;

}

Polynomial(const Polynomial &rhs){ //copy constructor

space = rhs.space;

if(space==0){

head=NULL;

return;

}

else{

Node *t = new Node();

head = t;

t->data=rhs.head->data;

Node *x = rhs.head->next;

while(x!=NULL){

Node *f = new Node();

f->data=x->data;

t->next=f;

t=t->next;

x=x->next;

}

}

}

Node* getHead() const{

return head;

}

void insertBack(int data){

Node* temp = new Node;

temp = head;

while(temp && temp->next){

temp = temp->next;

}

Node *node = newNode(data);

temp->next = node;

}

Polynomial& operator+=(const Polynomial& rhs){

Node *temp1 = rhs.getHead();

Node *temp2 = head;

while(temp1 && temp2){

temp2->data += temp1->data;

temp1 = temp1->next;

temp2= temp2->next;

}

while(temp2){

temp2 = temp2->next;

}

return *this;

}

int evaluate(int val){

Node* g = head;

int x = 1;

int k = 0;

while(g){

g->data *=x;

k += g->data;

g = g->next;

x*=val;

}

return k;

}

friend ostream & operator << (ostream &out, const Polynomial &p);

friend Polynomial operator + (Polynomial const &, Polynomial const &);

};

bool operator==(Polynomial& lhs, Polynomial& rhs) {

if (lhs.getspace() != rhs.getspace()) return false;

Node* lcurrent = lhs.getHead();

Node* rcurrent = rhs.getHead();

while (lcurrent != nullptr && rcurrent != nullptr) {

if (lcurrent->data != rcurrent->data) return false;

lcurrent = lcurrent->next;

rcurrent = rcurrent->next;

}

return true;

}

bool operator!=(Polynomial& lhs, Polynomial& rhs) {

return !(lhs==rhs);

}

ostream & operator << (ostream &out, const Polynomial& p){

Node* temp = new Node;

temp = p.getHead();

int i = 0;

while(temp != NULL){

if(p.getHead()->data==0){

cout<<"0";

}

else if(temp->data!=0){

if(i == 0){

out << temp->data;

i++;

}

else if(i == 1){

out << temp->data <<"x";

i++;

}

else{

out << temp->data << "x" << "^" << i++;

}

}

else {

out<<"";

i++;

}

temp = temp->next;

if(temp&&temp->data!=0){

out << " + ";

}

}

return out;

}

Polynomial operator + (Polynomial const &p1, Polynomial const &p2){

Polynomial p(p1);

Node *temp1 = p.getHead();

Node *temp2 = p2.getHead();

while(temp1 && temp2){

temp1->data += temp2->data;

temp1 = temp1->next;

temp2= temp2->next;

}

while(temp2){

p.insertBack(temp2->data);

temp2 = temp2->next;

}

return p;

}

void doNothing(Polynomial temp) {}

int main() {

//test constructor

Polynomial p1({17});

Polynomial p2({1, 2});

Polynomial p3({-1, 5});

Polynomial p4({5, 4, 3, 2, 1});

Polynomial has_a_zero({4, 0, 1, 7});

cout << "p1: " << p1 << endl;

cout << "p2: " << p2 << endl;

cout << "p3: " << p3 << endl;

cout << "p4: " << p4 << endl;

cout << "has_a_zero: " << has_a_zero << endl;

cout << "p2 + p3: " << (p2+p3) << endl;

cout << "p2 + p4: " << (p2+p4) << endl;

cout << "p4 + p2: " << (p4+p2) << endl;

//test copy constructor - the statement below uses the copy constructor

//to initialize poly3 with the same values as poly4

Polynomial p5(p4);

p5 += p3;

cout << "Polynomial p5(p4); "

<< "p5 += p3; ";

cout << "p4: " << p4 << endl;

cout << "p5: " << p5 << endl;

cout << "Calling doNothing(p5) ";

doNothing(p5);

cout << "p5: " << p5 << endl;

//tests the assignment operator

Polynomial p6;

cout << "p6: " << p6 << endl;

cout << boolalpha; // Causes bools true and false to be printed that way.

cout << "(p4 == p6) is " << (p4 == p6) << endl;

p6 = p4;

cout << "p6: " << p6 << endl;

cout << boolalpha;

cout << "(p4 == p6) is " << (p4 == p6) << endl;

//test the evaluaton

int x = 5;

cout << "Evaluating p1 at " << x << " yields: " << p1.evaluate(5) << endl;

cout << "Evaluating p2 at " << x << " yields: " << p2.evaluate(5) << endl;

Polynomial p7({3, 2, 1}); // 3x^2 + 2x + 1

cout << "p7: " << p7 << endl;

cout << "Evaluating p7 at " << x << " yields: " << p7.evaluate(5) << endl;

cout << boolalpha;

cout << "(p1 == p2) is " << (p1 == p2) << endl;

cout << "(p1 != p2) is " << (p1 != p2) << endl;

}