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Am not able to display the polynomial. Thr some problem in display function. Please help me out in this.

```
#include "stdafx.h"
#include <iostream>
using namespace std;
// Creating a NODE Structure
struct node
{
int coe,exp; // data
struct node *next; // link to next node and previous node
};
// Creating a class Polynomial
class polynomial
{
struct node *start,*ptrn,*ptrp;
public:
void get_poly(); // to get a polynomial
void show(); // show
void add(polynomial p1,polynomial p2); // Add two polynomials
void subtract(polynomial p1,polynomial p2); //Subtract2 polynomials
};
void polynomial::get_poly() // Get Polynomial
{
char c='y';
ptrn=ptrp=start=NULL;
while(c=='y' || c=='Y')
{
ptrn=new node;
//ptrp->next=ptrn;
if(start==NULL)
start=ptrn;
ptrp=ptrn;
cout<<"\nEnter the coefficient: ";
cin>>ptrn->coe;
cout<<"Enter the exponent: ";
cin>>ptrn->exp;
ptrn->next=NULL;
cout<<"Enter y to add more nodes: ";
cin>>c;
}
return;
}
void polynomial::show() // Show Polynomial
{
struct node *ptr;
ptr=start;
while(ptr->next!=NULL)
{
//ptr=start;
cout<<ptr->coe<<"X^"<<ptr->exp;
ptr=ptr->next;
if(ptr->next!=NULL)
cout<<"+";
}
cout<<"\b\b ";
}
/*void polynomial::show() // Show Polynomial
{
// cout<<"Inside Show";
struct node *ptr=start;
//cout << next ;
if(ptr)
{
cout<<"displaying polynomials"<<"\n";
if(ptr->next<0)
cout<<"-";
while(ptr)
{
cout<<ptr->coe<<"X^"<<ptr->exp;
ptr=ptr->next;
if(ptr)
if(ptr->coe > 0)
cout << " + ";
else
cout << " - ";
}
cout << "\n";
}
else
{
cout << "Display Polynomial: Polynomial does not exist\n";
}
}*/
void polynomial::add(polynomial p1,polynomial p2) // Add Polynomials
{
struct node *p1ptr,*p2ptr;
int coe,exp;
ptrn=ptrp=start=NULL;
p1ptr=p1.start;
p2ptr=p2.start;
while(p1ptr!=NULL && p2ptr!=NULL)
{
if(p1ptr->exp==p2ptr->exp) // If coefficients are equal
{
coe=p1ptr->coe+p2ptr->coe;
exp=p1ptr->exp;
p1ptr=p1ptr->next;
p2ptr=p2ptr->next;
}
else if(p1ptr->exp>p2ptr->exp)
{
coe=p1ptr->coe;
exp=p1ptr->exp;
p1ptr=p1ptr->next;
}
else if(p1ptr->exp<p2ptr->exp)
{
coe=p2ptr->coe;
exp=p2ptr->exp;
p2ptr=p2ptr->next;
}
ptrn=new node;
if(start==NULL)
start=ptrn;
ptrn->coe=coe;
ptrn->exp=exp;
ptrn->next=NULL;
//ptrp->next=ptrn;
ptrp=ptrn;
} // End of While
if(p1ptr==NULL)
{
while(p2ptr!=NULL)
{
coe=p2ptr->coe;
exp=p2ptr->exp;
p2ptr=p2ptr->next;
ptrn=new node;
if(start==NULL)
start=ptrn;
ptrn->coe=coe;
ptrn->exp=exp;
ptrn->next=NULL;
//ptrp->next=ptrn;
ptrp=ptrn;
}
}
else if(p2ptr==NULL)
{
while(p1ptr!=NULL)
{
coe=p1ptr->coe;
exp=p1ptr->exp;
p1ptr=p1ptr->next;
ptrn=new node;
if(start==NULL)
start=ptrn;
ptrn->coe=coe;
ptrn->exp=exp;
ptrn->next=NULL;
//ptrp->next=ptrn;
ptrp=ptrn;
}
}
} // End of addition
// Subtract two polynomials
void polynomial::subtract(polynomial p1,polynomial p2) // Subtract
{
struct node *p1ptr,*p2ptr;
int coe,exp;
ptrn=ptrp=start=NULL;
p1ptr=p1.start;
p2ptr=p2.start;
while(p1ptr!=NULL && p2ptr!=NULL)
{
if(p1ptr->exp==p2ptr->exp) // If coefficients are equal
{
coe=p1ptr->coe-p2ptr->coe;
exp=p1ptr->exp;
p1ptr=p1ptr->next;
p2ptr=p2ptr->next;
}
else if(p1ptr->exp>p2ptr->exp)
{
coe=p1ptr->coe;
exp=p1ptr->exp;
p1ptr=p1ptr->next;
}
else if(p1ptr->exp<p2ptr->exp)
{
coe=0-p2ptr->coe;
exp=p2ptr->exp;
p2ptr=p2ptr->next;
}
ptrn=new node;
if(start==NULL)
start=ptrn;
ptrn->coe=coe;
ptrn->exp=exp;
ptrn->next=NULL;
//ptrp->next=ptrn;
ptrp=ptrn;
} // End of While
if(p1ptr==NULL)
{
while(p2ptr!=NULL)
{
coe=0-p2ptr->coe;
exp=p2ptr->exp;
p2ptr=p2ptr->next;
ptrn=new node;
if(start==NULL)
start=ptrn;
ptrn->coe=coe;
ptrn->exp=exp;
ptrn->next=NULL;
//ptrp->next=ptrn;
ptrp=ptrn;
}
}
else if(p2ptr==NULL)
{
while(p1ptr!=NULL)
{
coe=p1ptr->coe;
exp=p1ptr->exp;
p1ptr=p1ptr->next;
ptrn=new node;
if(start==NULL)
start=ptrn;
ptrn->coe=coe;
ptrn->exp=exp;
ptrn->next=NULL;
//ptrp->next=ptrn;
ptrp=ptrn;
}
}
} // End of subtraction
int main()
{
// clrscr();
polynomial p1,p2,sum,diff;
cout<<"First Polynomial.\n";
p1.get_poly();
cout<<"\nSecond polynomial.\n";
p2.get_poly();
//clrscr();
cout<<"\nThe First polynomial is: ";
p1.show();
cout<<"\nThe second polynomial is: ";
p2.show();
cout<<"\n\nThe sum of two polynomials is: ";
sum.add(p1,p2);
sum.show();
cout<<"\n\nThe difference of two polynomials is: ";
diff.subtract(p1,p2);
diff.show();
return 0;
//getch();
}
```