Answer Happy

This code is complete. However, I need Someone to add
comments on what the code is doing for each line. Then I need a UML
diagram.
#include <iostream>
using namespace std;
double recursiveSquare(double, double);
int main() {
double x;
cout << "Input a number to find its square root: " <<
endl;
cin >> x;
double answer=recursiveSquare(x, x);
cout << "The sqaure root is " << answer <<
endl;
return 0;
}
double recursiveSquare(double x, double a)
{
double epsilon=0.000001;
double hold;
double divisor;
double level=a*a;
level=level-x;
if(level<0)
{
level=level*-1;
}
if(epsilon >= level)
{
return a;
}
else
{
hold=a*a;
hold=hold+x;
divisor=2*a;
hold=hold/divisor;
a=hold;
return recursiveSquare(x, a);
}
}