2 Polynomial Linked List

#include<stdio.h>

#include<stdlib.h>

struct node  {

    int coeff;

    int exp;

    struct node* next;

}*head1 = 0, *head2 = 0, *ptr1 = 0, *ptr2 = 0, *head = 0, *fin = 0, *temp, *fin;

struct node* insert(struct node* head, int co, int ex) {

    struct node* new1 = malloc(sizeof(struct node));

    new1->coeff = co;

    new1->exp = ex;

    new1->next = 0;

    if(head == 0 || ex > head->exp) {

        new1->next = head;

        head = new1;

    } else {

        temp = head;

        while(temp->next != 0 && temp->next->exp >= ex) {

            temp = temp->next;

        }

        new1->next = temp->next;

        temp->next = new1;

    }

    return head;

}

struct node* create(struct node* temp) {

    int terms, co, ex;

    printf("\nEnter no of terms : \t");

    scanf("%d", &terms);

    for(int i=0; i<terms; i++) {

        printf("\nEnter coeff and exp for %d term : \t", i+1);

        scanf("%d %d", &co, &ex);

        temp = insert(temp, co, ex);

    }

    return temp;

}

struct node* polyadd(struct node* head1, struct node* head2) {

    ptr1 = head1, ptr2 = head2;

    while(ptr1 != 0 && ptr2 != 0) {

        if(ptr1->exp == ptr2->exp) {

            fin = insert(fin, ptr1->coeff + ptr2->coeff, ptr1->exp);

            ptr1 = ptr1->next;

            ptr2 = ptr2->next;

        }

        else if(ptr1->exp > ptr2->exp) {

            fin = insert(fin, ptr1->coeff, ptr1->exp);

            ptr1 = ptr1->next;

        } else {

            fin = insert(fin, ptr2->coeff, ptr2->exp);

            ptr2 = ptr2->next;

        }

    }

    return fin;

}

void display(struct node* head) {

    if(head == NULL) {

        printf("List Empty");

    } else {

        temp = head;

        while(temp!=0) {

            printf("%d x^%d", temp->coeff, temp->exp);

            temp = temp->next;

            if(temp != NULL) {

                printf(" + ");

            } else {

                printf("\n");

            }

        }

    }

}

int main() {

    printf("\nCreate 1st polynomial");

    head1 = create(head1);

    printf("\n******************************************************\n");

    display(head1);

    printf("\nCreate 2nd polynomial");

    head2 = create(head2);

    printf("\n******************************************************\n");

    display(head2);

   

    fin = polyadd(head1, head2);

    printf("\n******************************************************\n");

    display(fin);

}