牛顿迭代法求方程根

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

double test_func0(double x)
{
    return (2*x*x*x - 4*x*x + 3*x - 6);
}

double test_func1(double x)
{
    return (6*x*x - 8*x + 3);
}

void newton(double *x, double precision)
{
    double x0, x1;
    x0 = *x;
    x1 = x0 - test_func0(x0) / test_func1(x0);
    while(fabs(x1 - x0) > precision)
    {
        x0 = x1;
        x1 = x0 - test_func0(x0) / test_func1(x0);
    }

    *x = x1;
}