Question

Add and subtract polynomials using linked lists:

The output should look like the following:

First polynomial: 1.3x^2 + 2.5x^4 + 5.3x^2 + 2.8x^1 + 3.8 Second polynomial: 2.5x^6 + 3.5x^4 -4.5x 3 + 4.9x^2 + 7.5x41 Resultant polynomial addition: 1.3x^2 + 2.5x^6 + 6x^4 -4.5x^3 + 10.2x^2 + 10.3x^1 + 3.8 Resultant polynomial subtraction : 1.3x^7 -2.5x^6 -1x^4 + 4.5x^3 + 0.4x^2 -4.7x^1 + 3.8

The code for the header file, Polynomial.h, is given as such:

***********HEADER*************

#include <iostream>
#include <cstdlib>

using namespace std;

class polyll { //this is class POLYLL, but all lower case
private:
struct polynode {
float coeff;
int exp;
polynode* link;
} * p;

public:
polyll();
void poly_append(float c, int e);
void display_poly();
void poly_add(polyll& l1, polyll& l2);
void poly_subtract(polyll& l1, polyll& l2);
~polyll();
};
polyll::polyll()
{
p = NULL;
}
void polyll::poly_append(float c, int e)

{
polynode* temp = p;

if (temp == NULL)
{
temp = new polynode;
p = temp;
}
else
{
while (temp->link != NULL)
temp = temp->link;

temp->link = new polynode;
temp = temp->link;
}
temp->coeff = c;
temp->exp = e;
temp->link = NULL;
}
void polyll::display_poly()

{
polynode* temp = p;
int f = 0;

cout << endl << " ";
while (temp != NULL)
{ if (f != 0)
{
if (temp->coeff > 0)
cout << " + ";
else
cout << " ";
}
if (temp->exp != 0)
cout << temp->coeff << "x^" << temp->exp;
else
cout << " " << temp->coeff;

temp = temp->link;
f = 1;
}
}

void polyll::poly_add(polyll& l1, polyll& l2) { //this function is POLYLL& L1, POLYLL& L2, but all lower case

}

void polyll::poly_subtract(polyll& l1, polyll& l2) { // Subtract the polynomials

}

polyll::~polyll()
{
polynode* q;
while (p != NULL) {
q = p->link;
delete p;
p = q;
}
}

Code in the main.cpp file is given as such:

**********MAIN**********

#include "Polynomial.h"
#include <iostream>
using namespace std;

int main()
{
polyll p1;
p1.poly_append(1.3, 7);
p1.poly_append(2.5, 4);
p1.poly_append(5.3, 2);
p1.poly_append(2.8, 1);
p1.poly_append(3.8, 0);
cout << "\n\n First polynomial:\n" ;
p1.display_poly();
polyll p2;
p2.poly_append(2.5, 6);
p2.poly_append(3.5, 4);
p2.poly_append(-4.5,3);
p2.poly_append(4.9, 2);
p2.poly_append(7.5, 1);
cout << "\n\n\n Second polynomial:\n";
p2.display_poly();
polyll p3;
p3.poly_add(p1, p2);
cout << "\n\n\n Resultant polynomial addition: \n";
p3.display_poly();

polyll p4;
p4.poly_subtract(p1, p2);
cout << "\n\n\n Resultant polynomial subtraction: \n";
p4.display_poly();

getchar();
}

Just need help with the add and subtract parts in the header. Thank you very much!

Answer 1

void polyll::poly_add(polyll& l1, polyll& l2) // Add Polynomials
{
polyll *l1ptr,*l2ptr;
int coeff,exp;
ptrn=ptrp=temp=NULL;
l1ptr=l1.temp;
l2ptr=l2.temp;
while(l1ptr!=NULL && l2ptr!=NULL)
{
if(l1ptr->exp==l2ptr->exp) // If coefffficients are equal
{
   coeff=l1ptr->coeff+l2ptr->coeff;
   exp=l1ptr->exp;
   l1ptr=l1ptr->link;
   l2ptr=l2ptr->link;
}
else if(l1ptr->exp>l2ptr->exp)
{
   coeff=l1ptr->coeff;
   exp=l1ptr->exp;
   l1ptr=l1ptr->link;
}
else if(l1ptr->exp<l2ptr->exp)
{
   coeff=l2ptr->coeff;
   exp=l2ptr->exp;
   l2ptr=l2ptr->link;
}
ptrn=new polyll;
if(temp==NULL)
   temp=ptrn;
ptrn->coeff=coeff;
ptrn->exp=exp;
ptrn->link=NULL;
ptrp->link=ptrn;
ptrp=ptrn;
} // End of While
if(l1ptr==NULL)
{
while(l2ptr!=NULL)
{
   coeff=l2ptr->coeff;
   exp=l2ptr->exp;
   l2ptr=l2ptr->link;
   ptrn=new polyll;
   if(temp==NULL)
   temp=ptrn;
   ptrn->coeff=coeff;
   ptrn->exp=exp;
   ptrn->link=NULL;
   ptrp->link=ptrn;
   ptrp=ptrn;
}
}
else if(l2ptr==NULL)
{
while(l1ptr!=NULL)
{
   coeff=l1ptr->coeff;
   exp=l1ptr->exp;
   l1ptr=l1ptr->link;
   ptrn=new polyll;
   if(temp==NULL)
   temp=ptrn;
   ptrn->coeff=coeff;
   ptrn->exp=exp;
   ptrn->link=NULL;
   ptrp->link=ptrn;
   ptrp=ptrn;
}
}
} // End of addition

// Subtract two polynomials
void polyll::poly_subtract(polyll& l1, polyll& l2) // Subtract
{
polyll *l1ptr,*l2ptr;
int coeff,exp;
ptrn=ptrp=temp=NULL;
l1ptr=l1.temp;
l2ptr=l2.temp;
while(l1ptr!=NULL && l2ptr!=NULL)
{
if(l1ptr->exp==l2ptr->exp) // If coefffficients are equal
{
   coeff=l1ptr->coeff-l2ptr->coeff;
   exp=l1ptr->exp;
   l1ptr=l1ptr->link;
   l2ptr=l2ptr->link;
}
else if(l1ptr->exp>l2ptr->exp)
{
   coeff=l1ptr->coeff;
   exp=l1ptr->exp;
   l1ptr=l1ptr->link;
}
else if(l1ptr->exp<l2ptr->exp)
{
   coeff=0-l2ptr->coeff;
   exp=l2ptr->exp;
   l2ptr=l2ptr->link;
}
ptrn=new polyll;
if(temp==NULL)
   temp=ptrn;
ptrn->coeff=coeff;
ptrn->exp=exp;
ptrn->link=NULL;
ptrp->link=ptrn;
ptrp=ptrn;
} // End of While
if(l1ptr==NULL)
{
while(l2ptr!=NULL)
{
   coeff=0-l2ptr->coeff;
   exp=l2ptr->exp;
   l2ptr=l2ptr->link;
   ptrn=new polyll;
   if(temp==NULL)
   temp=ptrn;
   ptrn->coeff=coeff;
   ptrn->exp=exp;
   ptrn->link=NULL;
   ptrp->link=ptrn;
   ptrp=ptrn;
}
}
else if(l2ptr==NULL)
{
while(l1ptr!=NULL)
{
   coeff=l1ptr->coeff;
   exp=l1ptr->exp;
   l1ptr=l1ptr->link;
   ptrn=new polyll;
   if(temp==NULL)
   temp=ptrn;
   ptrn->coeff=coeff;
   ptrn->exp=exp;
   ptrn->link=NULL;
   ptrp->link=ptrn;
   ptrp=ptrn;
}
}
} // End of subtraction

/* I have made the function according to my taken variable please replace it using find and replace feature in compile at last I replace some of major variable like parameter and class variable.

If you find difficulties please ask

Thank You!

*/

for addition

#include<bits/stdc++.h>
using namespace std;
  
struct Node
{
int coeff;
int pow;
struct Node *next;
};
  
void create_node(int x, int y, struct Node **temp)
{
struct Node *r, *z;
z = *temp;
if(z == NULL)
{
r =(struct Node*)malloc(sizeof(struct Node));
r->coeff = x;
r->pow = y;
*temp = r;
r->next = (struct Node*)malloc(sizeof(struct Node));
r = r->next;
r->next = NULL;
}
else
{
r->coeff = x;
r->pow = y;
r->next = (struct Node*)malloc(sizeof(struct Node));
r = r->next;
r->next = NULL;
}
}
void polyadd(struct Node *poly1, struct Node *poly2, struct Node *poly)
{
while(poly1->next && poly2->next)
{

if(poly1->pow > poly2->pow)
{
poly->pow = poly1->pow;
poly->coeff = poly1->coeff;
poly1 = poly1->next;
}
  
else if(poly1->pow < poly2->pow)
{
poly->pow = poly2->pow;
poly->coeff = poly2->coeff;
poly2 = poly2->next;
}
  
else
{
poly->pow = poly1->pow;
poly->coeff = poly1->coeff+poly2->coeff;
poly1 = poly1->next;
poly2 = poly2->next;
}

poly->next = (struct Node *)malloc(sizeof(struct Node));
poly = poly->next;
poly->next = NULL;
}
while(poly1->next || poly2->next)
{
if(poly1->next)
{
poly->pow = poly1->pow;
poly->coeff = poly1->coeff;
poly1 = poly1->next;
}
if(poly2->next)
{
poly->pow = poly2->pow;
poly->coeff = poly2->coeff;
poly2 = poly2->next;
}
poly->next = (struct Node *)malloc(sizeof(struct Node));
poly = poly->next;
poly->next = NULL;
}
}

void show(struct Node *node)
{
while(node->next != NULL)
{
printf("%dx^%d", node->coeff, node->pow);
node = node->next;
if(node->next != NULL)
printf(" + ");
}
}

int main()
{
struct Node *poly1 = NULL, *poly2 = NULL, *poly = NULL;

create_node(5,2,&poly1);
create_node(4,1,&poly1);
create_node(2,0,&poly1);
  
create_node(5,1,&poly2);
create_node(5,0,&poly2);
  
printf("1st Number: ");
show(poly1);
  
printf("\n2nd Number: ");
show(poly2);
  
poly = (struct Node *)malloc(sizeof(struct Node));
  
polyadd(poly1, poly2, poly);

printf("\nAdded polynomial: ");
show(poly);
  
return 0;
}