Polynomial Multiplication Using Circular Header Linked List

Polynomial Multiplication using Circular Linked List with header node

#include<stdio.h>

#include<stdlib.h>

struct node

{

             int coeff;

             int expon;

             struct node *link;

};

typedef struct node *NODE;

NODE getnode()

{

            NODE x;

            x =(NODE) malloc(sizeof(struct node));

            return x;

}

void display(NODE head);

NODE attach(int coeff, int expon, NODE head)

{

            NODE temp, cur;

            temp = getnode();

            temp->coeff = coeff;

            temp->expon = expon;

            cur = head->link;

            while(cur->link != head)

            {

                        cur = cur->link;

            }

            cur->link = temp;

            temp->link = head;

            return head;

}

NODE read_poly(NODE head)

{

            int i = 1, coeff, expon;

            printf("\nEnter the coefficient as -999 to end the polynomial ");

            while(1)

            {

                        printf("\nEnter the %d term:\n",i++);

                        printf("\n\tCoeff = ");

                        scanf("%d", &coeff);

                        if(coeff == -999)

                                    break;

                        printf("\n\tPow x = ");

                        scanf("%d", &expon);

                        head = attach(coeff, expon, head);

            }

              return head;

}

NODE poly_mult(NODE head1, NODE head2, NODE head3)

{

            NODE cur1, cur2;

            if(head1->link == head1 || head2->link == head2)

            {

                        printf("\nMultiplied polynomial is zero polynomial");

                        return;

            }

            cur1 = head1->link;

            while(cur1 != head1)

            {

                        cur2 = head2->link;

                        while(cur2!=head2)

                        {

                                    head3 =attach(cur1->coeff*cur2->coeff, cur1->expon+cur2->expon, head3);

                                   cur2=cur2->link;

                        }

                        cur1=cur1->link;

            }

            return head3;

}

void display(NODE head)

{

            NODE temp;

            if(head->link == head)

            {

                         printf("\nPolynomial does not exist");

                         return;

            }

            temp = head->link;

            while(temp != head)

            {

                         printf("%dx^%d", temp->coeff, temp->expon);

                         temp = temp->link;

                         if(temp != head)

                                    printf(" + ");

            }

}

void main()

{

             NODE head1, head2, head3;

            head1 = getnode();

            head2 = getnode();

            head3 = getnode();

            head1->link=head1;

            head2->link=head2;

            head3->link=head3;

              printf("\nEnter the first polynomial \n");

              head1=read_poly(head1);

              printf("\nEnter the second polynomial \n");

              head2=read_poly(head2);

            head3=poly_mult(head1, head2, head3);

                       

              printf("\nPolynomial 1:\t");

              display(head1);

              printf("\nPolynomial 2:\t");

              display(head2);

              printf("\nPolynomial Result:\t");

              display(head3);

}

Output:

Enter the first polynomial

Enter the coefficient as -999 to end the polynomial

Enter the 1 term:

        Coeff = 4

        Pow x = 2

Enter the 2 term:

        Coeff = 3

        Pow x = 1

Enter the 3 term:

        Coeff = -999

Enter the second polynomial

Enter the coefficient as -999 to end the polynomial

Enter the 1 term:

        Coeff = 7

        Pow x = 1

Enter the 2 term:

        Coeff = 9

        Pow x = 0

Enter the 3 term:

       Coeff = -999

Polynomial 1:   4x^2 + 3x^1

Polynomial 2:   7x^1 + 9x^0

Polynomial Result:      28x^3 + 36x^2 + 21x^2 + 27x^1