Newton Raphson Method

#include<stdio.h>

float r0; /*initial value of root */

struct polynomial {

int number_of_terms;

int exponent[10];

float coefficient[10];

} poly;

struct differenciated_polynomial {

int number_of_terms;

int exponent[10];

float coefficient[10];

} diff_poly;

float power(float x,int n) {

int i;

float pow=1;

for(i=0;i<n;i++)

pow = pow*x;

return pow;

}

void store_poly() {

int counter=0;

printf("\tEnter the number of terms for your polynomial .... ");

scanf("%d",&poly.number_of_terms);

while(counter<poly.number_of_terms) {

printf("\tEnter the value of coefficient for term  %d .... ",counter+1);

scanf("%f",&poly.coefficient[counter]);

printf("\tEnter the value of its exponent .... ");

scanf("%d",&poly.exponent[counter]);

counter++ ;

  }

printf("\n\n\tEnter initial approximation of the root ......");

scanf("%f",&r0);

}

void differenciate_poly() {

int i;

diff_poly.number_of_terms=poly.number_of_terms;

for(i=0;i<poly.number_of_terms;i++) {

diff_poly.coefficient[i]=poly.coefficient[i]*poly.exponent[i];

diff_poly.exponent[i]=poly.exponent[i]-1;

 }

}

float value_at_poly(float x) { /* to calculate f(x) */

int counter=0;

float value=0.00;

while(counter<poly.number_of_terms) {

value += poly.coefficient[counter] * power(x,poly.exponent[counter]);

counter++;

 }

return value;

}

float value_at_diff(float x) { /* to calculate f'(x) */

int counter=0;

float value=0.00;

while(counter<diff_poly.number_of_terms) {

value += diff_poly.coefficient[counter] * power(x,diff_poly.exponent[counter]);

counter++;

 }

return value;

}

void print_poly() {

int length=0;

printf("\t----------------------------------------------------------------------------------------\n");

printf("\n\tThe Entered polynomial is as follows ..... ");

while(length<poly.number_of_terms) {

if(poly.coefficient[length]!=0.0)

printf("(%f * X^ %d) ",poly.coefficient[length],poly.exponent[length]);

if(length!= poly.number_of_terms-1)

printf("+ ");

length++ ;

}

printf(" = 0 \n");

printf("\t------------------------------------------------------------------------------------------\n");

}

void print_diff_poly() {

int length=0;

printf("\t----------------------------------------------------------------------------------------\n");

printf("\n\tThe 1st order differenciation polynomial is as follows ..... ");

while(length<diff_poly.number_of_terms) {

if(diff_poly.coefficient[length]!=0.0)

printf("(%f * X^ %d) ",diff_poly.coefficient[length],diff_poly.exponent[length]);

if(length!=diff_poly.number_of_terms-1)

printf("+ ");

length++ ;

}

printf(" = 0 \n");

printf("\t------------------------------------------------------------------------------------------\n");

}

float find_root() {

int i;

float prev_r0;

for(i=0;i<20;i++) {

prev_r0 = r0;

r0 = prev_r0 - value_at_poly(prev_r0)/value_at_diff(prev_r0);

}

return r0;

}

main() {

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

printf("\t              DEMONSTRATION OF NEWTON-RAPHSON  METHOD\n");

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

printf("\t ENTER THE POLYNOMIAL  ........\n\n");

store_poly();

differenciate_poly();

print_poly();

print_diff_poly();

printf("\n\t================================================================\n");

printf("\t    Calculated value of Root (Newton-Raphson) = %f\n",find_root());

printf("\t============================================================\n");

}