A polynomial may be represented as a linked list where each

A polynomial may be represented as a linked list where each node contains the coefficient and exponent of a term of the polynomial. The polynomial 4 X^3 - 3 X^2 = 5 would be represented as the linked list. Write a program system that reads two polynomials, stores them as linked lists, adds them together, then its coefficient is the sum of the corresponding coefficient in both polynomials. (If sum is zero, term should be deleted).

Solution

//EXAMPLE PROGRAM FOR SINGLE LINKED LIST
# include <stdio.h>
# include <conio.h>
# include <alloc.h>
# include <stdlib.h>
struct list
{
int number;
struct list *next;
};
typedef struct list node;
node *first,*prev,*temp,*curr;

void create(void)
{
printf(\"\ Stop by -999\");
temp=(node *)(malloc(sizeof(node)));
printf(\"\ Enter the numbers \");
scanf(\"%d\",&temp->number);
while(temp->number!=-999)
{
temp->next=NULL;
if(first==NULL)
{
first=temp;
prev=first;
}
else
{
prev->next=temp;
prev=temp;
}
temp=(node *)(malloc(sizeof(node)));
scanf(\"%d\",&temp->number);
} //end of while
}

void delete1(void)
{
int num;
printf(\"\ Enter the number to delete \");
scanf(\"%d\",&num);
if(first->number==num)
{
first=first->next;
return;
}
else
{
prev=first;
curr=first->next;
while(curr->next!=NULL)
{
if(curr->number==num)
{
prev->next=curr->next;
return;
}
prev=curr;
curr=curr->next;
}
}
if(curr->number==num)
{
prev->next=NULL;
return;
}
printf(\"\ No such number\");
}

void insertbefore(void)
{
int nu;
temp=(node *)(malloc(sizeof(node)));
printf(\"\ Enter the number \");
scanf(\"%d\",&temp->number);
printf(\"\ Insert before which number \");
scanf(\"%d\",&nu);
temp->next=NULL;
prev=first;
curr=first;
if(first==NULL) //if the list is empty then we can insert in this way
{
first=temp;
return;
}
if(curr->number==nu)
{
temp->next=first;
first=temp;
return;
}
else
{
prev=curr;
curr=curr->next;
while(curr->next!=NULL)
{
if(curr->number==nu)
{
prev->next=temp;
temp->next=curr;
return;
}
prev=curr;
curr=curr->next;
}
}
if(curr->number==nu)
{
prev->next=temp;
temp->next=curr;
return;
}
printf(\"\ No such number \");
}
void insertafter(void)
{
int nu;
temp=(node *)(malloc(sizeof(node)));
printf(\"\ Enter the number \");
scanf(\"%d\",&temp->number);
printf(\"\ Insert after which number \");
scanf(\"%d\",&nu);
temp->next=NULL;
prev=first;
curr=first;
if(first==NULL) //if the list is empty then we can insert in this way
{
first=temp;
return;
}
if(curr->number==nu)
{
temp->next=curr->next;
curr->next=temp;
return;
}
else
{
prev=curr;
curr=curr->next;
while(curr->next!=NULL)
{
if(curr->number==nu)
{
temp->next=curr->next;
curr->next=temp;
return;
}
prev=curr;
curr=curr->next;
}
}
if(curr->number==nu)
{
curr->next=temp;
return;
}
printf(\"\ No such number \");
}

void print(void)
{
printf(\"\ The list is \ \");
printf(\" -----------\ \");
temp=first;
while(temp!=NULL)
{
printf(\"%d-->\",temp->number);
temp=temp->next;
}
printf(\"Nil\");
getch();
}

void main()
{
int ch=0;
first=NULL;
clrscr();
printf(\"\ Linked List creation \ \");
create();
clrscr();
while(ch!=5)
{
clrscr();
printf(\"\ 1.Insert Before\");
printf(\"\ 2.Insert After\");
printf(\"\ 3.Delete \");
printf(\"\ 4.Print \");
printf(\"\ 5.Exit \");
printf(\"\ Enter your choice \");
scanf(\"%d\",&ch);
switch(ch)
{
   case 1:
       insertbefore();
       print();
       break;
   case 2:
       insertafter();
       print();
       break;
   case 3:
       delete1();
       print();
       break;
   case 4:
       print();
       break;
   case 5:
       print();
       exit(1);
}
}
getch();
}