用牛顿迭代法求a^(1/3)

//用牛顿迭代法求a^(1/3)#include <iostream>#include <cmath>using namespace std;int main(){    const double EPS = 1e-6;//精度    double  a,x1,x2;    cout<<"请输入a："<<endl;    cin>>a;    x2=a;//第一个值取a    do    {        x1=x2;        x2=(2*x1+a/(x1*x1))/3;//计算新值    }    while (fabs(x2-x1)>=EPS);//控制精度    cout << a<<"的立方根是：" <<x2<< endl;    return 0;}