/* ---------------------------------- */
/* save as c04a.c                     */
/* ---------------------------------- */
#include "x_hfile.h"
/* ---------------------------------- */
# define   DEGREE  4
# define   COEFF   DEGREE + 1
/* ---------------------------------- */
int main(void)
{
int    n = COEFF;
double x = -6.;

double *Px = I_p(n);
double *Pt = I_p(n);
double *Pa = I_p(n);
double *Pq = I_p((n-1));

double a[COEFF]={1.,3.,-30.,-6.,56.};

 clrscrn();
 x = -4.;
 c_a_P(a,Px);
 printf(" If P(x) is : \n\n");
 p_P(Px);
 printf(" Find an lower bound for the zeros of P(x).\n\n");
 printf(" If we divide P(x) by : x - (%+.2f)\n\n",x);
 compute_horner(x,Px,Pt,Pa,Pq);
 p_horner(Px,Pt,Pa);
 printf(" The third row does not alternate in sign\n\n");
 printf(" So %+.3f is not a lower bound for the zeros of P(x)\n\n",x);
 stop();

 clrscrn();
 x = -8.;
 printf(" If we divide P(x) by : x - (%+.2f)\n\n",x);
 compute_horner(x,Px,Pt,Pa,Pq);
 p_horner(Px,Pt,Pa);
 printf(" The third row alternates in sign.\n\n");
 printf(" So %+.2f is a lower bound for the zeros of P(x).\n\n",x);
 
 stop();
 
 free(Px);
 free(Pt);
 free(Pa);
 free(Pq);
 
 return 0;
}