C :

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

double hanshu(float x);

int main()
{
	double j, k, x1, x2, x0;
	scanf("%lf%lf", &x1, &x2);
/*	while (hanshu(x1)*hanshu(x2) > 0)
		scanf("%lf%lf", &x1, &x2);
*/
	while (fabs(hanshu(x0)) > 1e-6)
	{
		x0 = (x1+x2) / 2;
		if (hanshu(x0)*hanshu(x1) < 0)
			x2 = x0;
		else
			x1 = x0;
	}
	printf("%.6f\n", x0);
}

double hanshu(float x)
{
	double y;
	y = 2*pow(x, 3) - 4*pow(x, 2) + 3*x - 6;
	return y;
}

C++ :

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

const double eps=1e-6;

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

int main()
{
	double a,b;
	while(scanf("%lf%lf",&a,&b)!=EOF)
	{
		double mid;
		while(fabs(a-b)>eps)
		{
			mid=(a+b)/2;
			if(fun(mid)*fun(a)>0)
				a=mid;
			else if(fun(mid)*fun(b)>0)
				b=mid;
			else
				break;
		}
		printf("%lf\n",mid);
	}
	return 0;
}