C++代码实现牛顿迭代法求数的立方根

#include<iostream>

#include<math.h>
using namespace std;

float fun(float guess, float x)

{
if (abs(guess*guess*guess - x) < 0.000001)
return guess;
else
{
return fun((x / guess / guess + 2 * guess) / 3, x);
}

}

int main()

{
float a, b;
while (cin >> a >> b)//a为猜测的立方根，b为实际所要求的立方根。
cout << fun(a, b) << endl;

}