Un poco de codigo C

/*****************************************************************************
* *
* -------------------------------- root.c -------------------------------- *
* *
*****************************************************************************/
#include <math.h>
#include "nummeths.h"
/*****************************************************************************
* *
* --------------------------------- root --------------------------------- *
* *
*****************************************************************************/
int root(double (*f)(double x), double (*g)(double x), double *x, int *n,
double delta) {
int satisfied,
i;
/*****************************************************************************
* *
* Use Newton's method to find a root of f. *
* *
*****************************************************************************/
i = 0;
satisfied = 0;
while (!satisfied && i + 1 < *n) {
/**************************************************************************
* *
* Determine the next iteration of x. *
* *
**************************************************************************/
x[i + 1] = x[i] - (f(x[i]) / g(x[i]));
/**************************************************************************
* *
* Determine whether the desired approximation has been obtained. *
* *
**************************************************************************/

if (fabs(x[i + 1] - x[i]) < delta)
satisfied = 1;
/**************************************************************************
* *
* Prepare for the next iteration. *
* *
**************************************************************************/
i++;
}
/*****************************************************************************
* *
* Even without iterating, indicate that one value has been stored in x. *
* *
*****************************************************************************/
if (i == 0)
*n = 1;
else
*n = i + 1;
/*****************************************************************************
* *
* Return whether a root was found or the maximum iterations were reached. *
* *
*****************************************************************************/
if (satisfied)
return 0;
else
return -1;
}