用迭代法求x=根a

#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    double a,x0,x1;
    cin>>a;
    x0=a/2;
    x1=(x0+a/x0)/2;
    while(fabs(x0-x1)>=(1e-5))
    {
        x0=x1;
        x1=(x0+a/x0)/2;
    }
    cout<<x1<<endl;
    return 0;
}