#include<stdio.h>
#include<math.h>
#include<stdlib.h>
float calc(float x)
{
    return x*x*x-4*x-9;
}

void func(float a, float b)
{
    float fa=calc(a),fb=calc(b),fc;
   float c,pc=-1;
    int p,itr;
    float tol;
    if(fa*fb>0)
    {
        int a1,b1;
        printf("Try Again ! ! !\n");
        printf("Enter 2 values");
        scanf("%f%f",&a1,&b1);
        func(a1,b1);
    }
    else if(fa*fb==0)
    {
        if(fa==0)
            printf("root=%f\n",a);
        if(fb==0)
        {
            printf("root=%f\n",b);
        }

    }
    else
    {
        printf("Enter precision and iteration");
        scanf("%f%d",&tol,&itr);

        for(int i=0;i<itr;i++)
        {
            c=(a+b)/2;

            fc=calc(c);

            if(fc==0)
                printf("root=%d\n",c);
            else if(fa*fc<0)
            {
                b=c;
            }
            else
            {
                a=c;
            }
            if(fabs(c-pc)<tol)
            {
                printf("solution  %f \n",c);
                break;
            }

            if(i==itr-1)
            printf("Need more iteration");

            pc=c;

        }

    }

}

int main()
{
    printf("Enter 2 val");
    float a,b;
    scanf("%f%f",&a,&b);
    func(a,b);
}