Assignment 10

Assignment no.:10
Title: Polynomial using a circular linked list using a menu driven program to perform addition,multiplication and evaluation.

#include<stdio.h>
#include<malloc.h>
#include<math.h>

typedef struct  node
 {
	int power;
	float coeff;
	struct node *next;
 }node;

	node *insert(node *head,int power1,float coeff1);
	node *create();
	node *padd(node *p1,node *p2);
	node *pmul(node *p1,node *p2);
	float eval(node *p1,float x);
	void print(node *head);

node *insert(node *head,int power1,float coeff1)
      {
	node *p,*q;
	/*terms are stored in decreasing  order of power*/
	/*pointer is used to locate the correct place of insertion.
	  pointer p is used to store the address of the node created for
	 the current term.If a term with same power is found,coefficients
	 are added*/
	p=(node*) malloc(sizeof(node));
	p->power=power1;
	p->coeff=coeff1;
	p->next=NULL;
	if(head==NULL) //Empty linked list
	   {
		head=p;
		head->next=head;
		return(head);
	   }
	if(power1<head->power)//lowest power,inserted at the end
	   {
		p->next=head->next;
		head->next=p;
		head=p;
		return(head);
	   }
	if(power1==head->power) //add coefficients
	   {
		head->coeff=head->coeff+coeff1;
		return(head);
	   }

	 q=head;
	 while(q->next!=head && power1<=q->next->power) //locate the postion for insertion
		q=q->next;
	 if(p->power==q->power)
		q->coeff=q->coeff+coeff1;
	 else
	   {
		p->next=q->next;
		q->next=p;
	   }
	return(head);
  }
 node *create()
   {
	int n,i,power1;
	float coeff1;
	node *head=NULL;
	printf("\nEnter No. of Terms:");
	scanf("%d",&n);
	printf("\nenter a term as a tuple of (power,coefficient) : ");
	for(i=1;i<=n;i++)
	   {
		scanf("%d%f",&power1,&coeff1);
		head=insert(head,power1,coeff1);
	   }
       return(head);
  }

 node *padd(node *p1,node *p2)
 {
	node *p;
	node *head=NULL;
	int power;float coeff;
	p=p1->next;
	do     //insert the first polynomial
	   {
		head=insert(head,p->power,p->coeff);
		p=p->next;
	   } while(p!=p1->next);
	p=p2->next;
	do  //insert the second polynomial
	   {
		head=insert(head,p->power,p->coeff);
		p=p->next;
	 } while(p!=p2->next);
	return(head);
  }

 node *pmul(node *p1,node *p2)
 {
	node *head1,*head2;
	node *head=NULL;
	head2=p2->next;
	do   //for every term of the second polynomial
	   {
		head1=p1->next;
		do  //multiply with every term of the first polynomial
		   {	
                               for(p=head1;p!=NULL;p=p->next)
			head=insert(head,head1->power+head2->power,head1->coeff * head2->coeff);
			head1=head1->next;
		    }while(head1!=p1->next);
		head2=head2->next;
	   }while(head2!=p2->next);
	return(head);
 }

 float eval(node *head,float x)
 {
	float value=0.00,t;
int r,i;
	node *p;
	p=head->next;
	do
	  {r=1;
for(i=1;i<=p->power;i++)
 {
  t=x;
  r=r*t;
 }
		value=value+p->coeff * r;
		p=p->next;
	  }while(p!=head->next);
	return(value);
 }

 void print( node *head)
 {
	node *p;
	p=head->next;
	printf("\n");
	do
	   {
		printf("6.2%fx^%d   ",p->coeff,p->power);
		p=p->next;
	   }while(p!=head->next);
 }
 void main()
  {
     node *p1,*p2,*p3;
     int ch;
     float value,x;
     p1=p2=p3=NULL;
      do
     {
     printf("\n1.create first polynomial\n2.create second polynomial\n3.print first polynomial\n4.print second polynomial\n5.add\n6.multiply\n7.evaluate first polynomial\n8.exit");

 printf("\n enter your choice");
    scanf("%d",&ch);
     switch(ch)
     {
    case 1:p1=create();
    break;
    case 2:p2=create();
    break;
    case 3:print(p1);
    break;
    case 4:print(p2);
    break;
    case 5:p3=padd(p1,p2);
           print(p3);
    break;
    case 6:p3=pmul(p1,p2);
           print(p3);
    break;
    case 7:
           printf("\n enter the value of x");
           scanf("%f",&x);
          value=eval(p1,x);
           printf("\n evaluated value=%6.2f",value);
           break;
     
    default:printf("\n invalid choice");
     }
     }while(ch!=8);
   }