poly_add.c File Reference

Implementation of Addition of two polynomials More...

#include <stdio.h>
#include <stdlib.h>

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Data Structures
struct	term
	identifier for single-variable polynomial coefficients as a linked list More...

Functions
void	free_poly (struct term *poly)
	Frees memory space. More...
void	create_polynomial (struct term **poly, int coef, int pow)
	The function will create a polynomial. More...
void	poly_add (struct term **pol, struct term *poly1, struct term *poly2)
	The function will add 2 polynomials. More...
void	display_polynomial (struct term *poly)
	The function will display the polynomial. More...
static void	test1 (struct term *poly1, struct term *poly2, struct term *poly3)
	Test function 1. More...
static void	test2 (struct term *poly1, struct term *poly2, struct term *poly3)
	Test function 2. More...
static void	test3 (struct term *poly1, struct term *poly2, struct term *poly3)
	Test function 3. More...
int	main (void)
	Main function. More...

Detailed Description

Implementation of Addition of two polynomials

Author

Ankita Roy Chowdhury

This code takes two polynomials as input and prints their sum using linked list. The polynomials must be in increasing or decreasing order of degree. Degree must be positive.

Function Documentation

create_polynomial()

void create_polynomial	(	struct term **	poly,
		int	coef,
		int	pow
	)

The function will create a polynomial.

Parameters

poly	stores the address of the polynomial being created
coef	contains the coefficient of the node
pow	contains the degree

Returns

none

{
    // Creating the polynomial using temporary linked lists
    struct term *temp1, *temp2;
    temp1 = *poly;  // Contains the null pointer
 
    // Initiating first term
    if (temp1 == NULL)
    {
        temp2 = (struct term *)malloc(
            sizeof(struct term));  // Dynamic node creation
        temp2->coef = coef;
        temp2->pow = pow;
        // Updating the null pointer with the address of the first node of the
        // polynomial just created
        *poly = temp2;
        temp2->next = NULL;  // Increasing the pointer temp2
    }
    // Creating the rest of the nodes
    else
    {
        temp2->next = (struct term *)malloc(
            sizeof(struct term));  // Dynamic node creation
        temp2 = temp2->next;       // Increasing the pointer temp2
        temp2->coef = coef;
        temp2->pow = pow;
        temp2->next = NULL;
    }
}

display_polynomial()

void display_polynomial

(

struct term *

poly

)

The function will display the polynomial.

Parameters

poly	first term of the polynomial to be displayed

Returns

none

{
    while (poly != NULL)
    {
        printf("%d x^%d", poly->coef, poly->pow);
        poly = poly->next;
        if (poly != NULL)
        {
            printf(" + ");
        }
    }
}

free_poly()

void free_poly

(

struct term *

poly

)

Frees memory space.

Parameters

poly	first term of polynomial

Returns

void

{
    if (!poly)
    {
        return;  // NULL pointer does not need delete
    }
    else
    {
        while (!poly->next)
        {
            free(poly->next);  // Deletes next term
        }
        free(poly);  // delete the current term
    }
}

main()

int main

(

void

)

Main function.

Returns

0 on exit

{
    struct term *poly1 = NULL, *poly2 = NULL, *poly3 = NULL;
    test1(poly1, poly2, poly3);
    test2(poly1, poly2, poly3);
    test3(poly1, poly2, poly3);
 
    return 0;
}

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poly_add()

void poly_add	(	struct term **	pol,
		struct term *	poly1,
		struct term *	poly2
	)

The function will add 2 polynomials.

Parameters

poly1	first polynomial of the addition
poly2	second polynomial of the addition
pol	the resultant polynomial

{
    // Creating a temporary linked list to store the resultant polynomial
    struct term *temp = (struct term *)malloc(sizeof(struct term));
    temp->next = NULL;
    *pol =
        temp;  //*pol always points to the 1st node of the resultant polynomial
 
    // Comparing the powers of the nodes of both the polynomials
    // until one gets exhausted
    while (poly1 && poly2)
    {
        /* If the power of the first polynomial is greater than the power of the
       second one place the power and coefficient of that node of the first
       polynomial in temp and increase the pointer poly1
       */
        if (poly1->pow > poly2->pow)
        {
            temp->coef = poly1->coef;
            temp->pow = poly1->pow;
            poly1 = poly1->next;
        }
        /* If the power of the second polynomial is greater than the power of
          the first one place the power and coefficient of that node of the
          second polynomial in temp and increase the pointer poly2
        */
        else if (poly1->pow < poly2->pow)
        {
            temp->coef = poly2->coef;
            temp->pow = poly2->pow;
            poly2 = poly2->next;
        }
        /* If both of them have same power then sum the coefficients
          place both the summed coefficient and the power in temp
          increase both the pointers poly1 and poly2
        */
        else
        {
            temp->coef = poly1->coef + poly2->coef;
            temp->pow = poly1->pow;
            poly1 = poly1->next;
            poly2 = poly2->next;
        }
        /* If none of the polynomials are exhausted
         dynamically create a node in temp
         */
        if (poly1 && poly2)
        {
            temp->next = (struct term *)malloc(
                sizeof(struct term));  // Dynamic node creation
            temp = temp->next;         // Increase the pointer temp
            temp->next = NULL;
        }
    }
    /* If one of the polynomials is exhausted
    place the rest of the other polynomial as it is in temp
    by creating nodes dynamically
    */
    while (poly1 || poly2)
    {
        temp->next = (struct term *)malloc(
            sizeof(struct term));  // Dynamic node creation
        temp = temp->next;         // Increasing the pointer
        temp->next = NULL;
 
        /* If poly1 is not exhausted
        place rest of that polynomial in temp
        */
        if (poly1)
        {
            temp->coef = poly1->coef;
            temp->pow = poly1->pow;
            poly1 = poly1->next;
        }
        /* If poly2 is not exhausted
       place rest of that polynomial in temp
       */
        else if (poly2)
        {
            temp->coef = poly2->coef;
            temp->pow = poly2->pow;
            poly2 = poly2->next;
        }
    }
}

test1()

static void test1 ( struct term *  poly1, struct term *  poly2, struct term *  poly3  )

static

Test function 1.

Polynomial 1 is 5 x^2 + 3 x^1 + 2 x^0 Polynomial 2 is 7 x^3 + 9 x^1 + 10 x^0 Resultant polynomial is 7 x^3 + 5 x^2 + 12 x^1 + 12 x^0

Returns

void

{
    printf("\n----Test 1----\n");
    printf("\nFirst Polynomial:\n");  // Defining the 1st polynomial
    create_polynomial(&poly1, 5, 2);
    create_polynomial(&poly1, 3, 1);
    create_polynomial(&poly1, 2, 0);
    display_polynomial(poly1);
 
    printf("\nSecond Polynomial:\n");  // Defining the 2nd polynomial
    create_polynomial(&poly2, 7, 3);
    create_polynomial(&poly2, 9, 1);
    create_polynomial(&poly2, 10, 0);
    display_polynomial(poly2);
 
    poly_add(&poly3, poly1, poly2);  // Adding the two polynomials
    printf("\nResultant polynomial:\n");
    display_polynomial(poly3);
    printf("\n");
 
    // Frees memory space
    free_poly(poly1);
    free_poly(poly2);
    free_poly(poly3);
}

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test2()

static void test2 ( struct term *  poly1, struct term *  poly2, struct term *  poly3  )

static

Test function 2.

Polynomial 1 is 3 x^5 + 1 x^4 + 2 x^3 + -2 x^1 + 5 x^0 Polynomial 2 is 2 x^5 + 3 x^3 + 7 x^1 + 2 x^0 Resultant polynomial is 5 x^5 + 1 x^4 + 5 x^3 + 5 x^1 + 7 x^0

Returns

void

{
    printf("\n----Test 2----\n");
    printf("\nFirst Polynomial:\n");  // Defining the 1st polynomial
    create_polynomial(&poly1, 3, 5);
    create_polynomial(&poly1, 1, 4);
    create_polynomial(&poly1, 2, 3);
    create_polynomial(&poly1, -2, 1);
    create_polynomial(&poly1, 5, 0);
 
    display_polynomial(poly1);
 
    printf("\nSecond Polynomial:\n");  // Defining the 2nd polynomial
    create_polynomial(&poly2, 2, 5);
    create_polynomial(&poly2, 3, 3);
    create_polynomial(&poly2, 7, 1);
    create_polynomial(&poly2, 2, 0);
 
    display_polynomial(poly2);
 
    poly_add(&poly3, poly1, poly2);  // Adding the two polynomials
    printf("\nResultant polynomial:\n");
    display_polynomial(poly3);
    printf("\n");
 
    // Frees memory space
    free_poly(poly1);
    free_poly(poly2);
    free_poly(poly3);
}

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test3()

static void test3 ( struct term *  poly1, struct term *  poly2, struct term *  poly3  )

static

Test function 3.

Polynomial 1 is -12 x^0 + 8 x^1 + 4 x^3 Polynomial 2 is 5 x^0 + -13 x^1 + 3 x^3 Resultant polynomial is -7 x^0 + -5 x^1 + 7 x^3

Returns

void

{
    printf("\n----Test 3----\n");
    printf("\nFirst Polynomial:\n");  // Defining the 1st polynomial
    create_polynomial(&poly1, -12, 0);
    create_polynomial(&poly1, 8, 1);
    create_polynomial(&poly1, 4, 3);
 
    display_polynomial(poly1);
 
    printf("\nSecond Polynomial:\n");  // Defining the 2nd polynomial
    create_polynomial(&poly2, 5, 0);
    create_polynomial(&poly2, -13, 1);
    create_polynomial(&poly2, 3, 3);
 
    display_polynomial(poly2);
 
    poly_add(&poly3, poly1, poly2);  // Adding the two polynomials
    printf("\nResultant polynomial:\n");
    display_polynomial(poly3);
    printf("\n");
 
    // Frees memory space
    free_poly(poly1);
    free_poly(poly2);
    free_poly(poly3);
}

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