2 70 points A C program can represent a real polynomial px o

2. (70 points) A C program can represent a real polynomial p(x) of degree n as an array of the real

coefficients a0 a1, …, an.

p(x) = a0 + a1x + a2x2 …, an xn

Write a C program that inputs a polynomial of degree 8 and then evaluates the polynomial at variousvalues of x. The output should have two decimal digits.

Enter the eight coefficients: 1.2 3 2.4 4 1 9.1 3 0

Enter x: 4.4

Output: 37552.73

1) Name your program poly.c.
2) As part of the solution, write and call the function get_poly()  with the following prototype.

The get_poly() function should fill the array of eight coefficients.

void get_poly(double *coeff);

The get_poly() function should use pointer arithmetic – not subscripting – to visit arrayelements. In other words, eliminate the loop index variables and all use of the [] operator inthe function.

3) As part of the solution, write and call the function eval_poly()  with the followingprototype.

double eval_poly(double *coeff, double x);

4) You might need the pow function in math.h library to calculate the result of raising x tothe power y. The function prototype of the pow function:

double pow(double x, double y);

5) Compile the program with –lm:  gcc -lm -Wall poly.c

Solution

#include <stdio.h>
void get_poly(double *coeff)
{
   printf(\"Enter the eight coefficients:\");
   int i;
   for(i=0;i<8;i++)
   {
       scanf(\"%lf\",coeff+i);
   }
}
double pow(double x, double y)
{
   int i;
   double ans=1;
   for(i=0;i<y;i++)
   {
       ans = ans*x;
   }
   return ans;
}
double eval_poly(double *coeff, double x)
{
  
   double ans=0;
   int i;
   for(i=0;i<8;i++)
   {
       ans = ans + (*(coeff+i))*pow(x,i);
   }
   return ans;
}
int main()
{
   double coeff[8];
   get_poly(coeff);
   double x;
   printf(\"Enter x:\");
   scanf(\"%lf\",&x);
   double ans = eval_poly(coeff,x);
   printf(\"Output: %.2lf\ \",ans);
   return 0;
}