浮点数二分之数的三次方根

输入一个数，求其三次方根。

解题代码：

# include 
using namespace std;
int main()
{
	double x;
	cin >> x;
	double a = 0, b = x;
	while(b-a>1e-7)
	{
		double mid = (a + b) / 2;
		if (mid * mid * mid >= x)b = mid;
		else a = mid;
	}
	printf("%lf", a);
	return 0;
}