Addition of polynomial using Linked List

//Program to add two polynomials using singly linked list.
 #include<stdio.h>
 #include<conio.h>
 #include<stdlib.h>
 struct node
 {
    int coeff,exp;
    struct node *link;
 };
 void display(struct node *t)
 {
    printf("\n The resultant polynomial is : ");
    while(t->link!=NULL)
    {
        printf("%dx^%d+",t->coeff,t->exp);
        t=t->link;
    }
    printf("%dx^%d",t->coeff,t->exp);
 }
 void add(struct node *p,struct node *q)
 {
    struct node *temp,*s;
    s=NULL;
    while(p!=NULL && q!=NULL)
    {
        struct node *r=(struct node*)malloc(sizeof(struct node));
        if(p->exp==q->exp)
        {
            r->coeff=p->coeff+q->coeff;
            r->exp=p->exp;
            r->link=NULL;
            p=p->link;
            q=q->link;
        }
        else if(p->exp>q->exp)
        {
            r->exp=p->exp;
            r->coeff=p->coeff;
            r->link=NULL;
            p=p->link;
        }
        else if(p->exp<q->exp)
        {
            r->exp=q->exp;
            r->coeff=q->coeff;
            r->link=NULL;
            q=q->link;
        }
        if(s==NULL)
            s=r;
        else
        {
            temp=s;
            while(temp->link!=NULL)
                temp=temp->link;
            temp->link=r;
        }
    }
    if(p==NULL && q==NULL)
    {
        goto x;
    }
    else if(p!=NULL)
    {
        temp=s;
        while(temp->link!=NULL)
            temp=temp->link;
        temp->link=p;
    }
    else if(q!=NULL)
    {
        temp=s;
        while(temp->link!=NULL)
            temp=temp->link;
        temp->link=q;
    }
    x:
        display(s);
 }
 void main()
 {
    int c,e,ch;
    struct node *p,*last,*q,*temp1;
    clrscr();
    //Creation of first linked list.
    p=NULL;  last=NULL;
    printf("\n For first linked list.");
    do
    {
        printf("\n Enter coeff and exp : ");
        scanf("%d %d",&c,&e);
        temp1=(struct node*)malloc(sizeof(struct node));
        temp1->coeff=c;
        temp1->exp=e;
        temp1->link=NULL;
        if(last==NULL)
        {
            p=temp1;
            last=p;
        }
        else
        {
            last->link=temp1;
            last=temp1;
        }
        printf("\n Do u want to add some more nodes (1 or 0): ");
        scanf("%d",&ch);
    }while(ch==1);
    //Creation of second linked list.
    q=NULL;  last=NULL;
    printf("\n For second linked list.");
    do
    {
        printf("\n Enter coeff and exp : ");
        scanf("%d %d",&c,&e);
        temp1=(struct node*)malloc(sizeof(struct node));
        temp1->coeff=c;
        temp1->exp=e;
        temp1->link=NULL;
        if(last==NULL)
        {
            q=temp1;
            last=q;
        }
        else
        {
            last->link=temp1;
            last=temp1;
        }
        printf("\n Do u want to add some more nodes (1 or 0): ");
        scanf("%d",&ch);
    }while(ch==1);
    add(p,q);
    getch();
 }