#include <stdio.h>

double   p(double);
double   root(double (*)(double), double, double);

int main(void)
{
   double   x;

   x = root(p, 0.0, 3.0);
   printf("%s%.16f\n%s%.16f\n",
      "Approximate root: ", x,
      "  Function value: ", p(x));
   return 0;
}