Question

I need someone to fix my C Program Code
Firstly I will post the Q and the input and the outputs

Then the code

In this problem, you will use Bisection method to find a root of a polynomial Write a C program to find a root of a cubic polynomial p(x)-a x^3 + b x^2 +cx-d:0 in the interval [-50,50] if it exists. You program will first prompt for and read the coefficients a, b, c, and d of the polynomial Step#1: Locate the interval [x0.xl] containing the root as follows: - fix x0 to -50. Also initialize x1 to -50 - for each value of x starting from -50 to 50 with increment of 1 If l p(x)| epsilon-> display the value of x as the root and stop If p(x)*p(x0)c0->assign x to x1 and get outside the loop (using break statement) ● . Step#2: Finding the root: -After the loop, if x1 is still-50-> display "No root found inside [-50,50] “ and terminate If not->The root is in the latest interval [x0,x1]. Then apply the following bisection procedure method Compute xm (x1+x0)/2 which represents the middle of the interval [x0,x1] While Ip(xm)epsilon o o . If p(x0)*p(xm) <0 -> root between x0 and x1, so x1 xm if p(xm)*p(x1) >0 ->root between xm and x1, so x0 xm . update xm (x0+x1)/2 Display the value of the root found and the number of iterations (repetitions) to obtain the root. Note: Define epsilon as a constant with a value = 1E-6 Below are 3 sample runs Enter a,b,c,d of axA3+bxA2+cx+d0: 0.5 0.88 -1.2 7.5 e polynominal has root at x=-3.591302 Found after 27 iterations Enter a,b,c,d of axA3+bxA2+cx+d-02.5 45.2 7.8 55.6 e polynominal has root at x=18.316626 Found after 35 iterations Enter a,b,c,d of axA3+bxA2+cx+d-0: 0.5 87.8 45.2 23.4 No root found in the interval [-50,50]

Secondly the code

===================================

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

int main()
{
   double a,b,c,d,l,x,x_0,x_1,x_mid,p_x,p_0,p_1,p_mid,E=1e-6;
int i1,i2;
  
  
   printf("Enter a,b,c,d of ax^3+bx^2+cx+d=0: ");
scanf("%lf%lf%lf%lf",&a,&b,&c,&d);
x_0=-50;x_1=-50;x=-50;p_0=a*(pow(x_0,3))+b*(pow(x_0,2))+c*x_0+d;i1=0;i2=0;
do{
       p_x=a*x*x*x+b*x*x+c*x+d;
       l=p_x*p_0;
       if(l<0){
       x_1=x;}
       i1=i1+1;x++;}
       while(fabs(p_x)>=E && x<50);   
       if(fabs(p_x)<E){
   printf("the polynominal has root at x=%.6f \nfound after %d iterations",x,i1);}
       else if(x_1!=-50){
           for(x_mid=(x_0+x_1)/2;fabs(p_mid)>E;x_mid=(x_0+x_1)/2){
           i2++;
           p_mid=a*(pow(x_mid,3))+b*(pow(x_mid,2))+c*x_mid+d;
           p_0=a*(pow(x_0,3))+b*(pow(x_0,2))+c*x_0+d;
           p_1=a*(pow(x_1,3))+b*(pow(x_1,2))+c*x_1+d;if(p_0*p_mid<0)
           {x_1=x_mid;}else if(p_mid*p_1<0){x_0=x_mid;}
           }if(a==-2.5){i2=i2+1;}
       printf("the polynominal has root at x=%.6f \nfound after %d iterations",x_mid,i2);}
   else printf("No root found inside the interval -50 to 50 ");   
           return 0;}

============================================

Answer 1

#include<stdio.h>
#include<math.h>
#define EPSILON 0.000001

void main()
{
   /* Variable Declaration */
   int i,a,b,c,d,x,count = 0;;
   double px,px0,px1,xm,pxm;
  
   /*Fixing x0 and x1 */
   int x0 = -50;
   int x1 = -50;
//ax^3 + bx^2 + cx + d = 0
   /*Taking Input */
     
   printf("Enter the coefficients a,b,c,d: ");
   scanf("%d%d%d%d",&a,&b,&c,&d);
  
   /* Calculate px0 */
  
   px0 = a*pow(x0,3) + b*pow(x0,2) + c*pow(x0,1) + d;
   /* Step 1 */
  
   for(x = -50; x <= 50; x++){
   /*Taking absolute value of px */
      
       px = a*pow(x,3) + b*pow(x,2) + c*pow(x,1) + d;
      
       if(abs(px) < EPSILON){
           count++;
           printf("Root : %d\n",x);
           printf("Iterations(Repetition) : %d\n",count);
           return;
       }
      
       else if((px*px0)< 0.0){
           x1 = x;
           break;
       }
   }
   /* Step -2 */
   if(x1 == -50){
       printf("No root found inside [-50,50]");
       return;
   }else{
      
       xm = (x1+x0)/2;
       pxm = a*pow(xm,3) + b*pow(xm,2) + c*pow(xm,1) + d;
       while(pxm >= EPSILON){
           count++;
          
           px0 = a*pow(x0,3) + b*pow(x0,2) + c*pow(x0,1) + d;
           pxm = a*pow(xm,3) + b*pow(xm,2) + c*pow(xm,1) + d;
          
           if((px0 * pxm )< 0) x1 = xm;
          
           px1 = a*pow(x1,3) + b*pow(x1,2) + c*pow(x1,1) + d;
          
           if((pxm*px1)<0) x0 = xm;
          
           xm = (x0 + x1)/2;
       }
       printf("root is : %lf\n",xm);
       printf("Iterations(Repetitions) : %lf",count);  
   }
}