#include <iostream>
#include <cmath>
using namespace std;
double mySqrt(double x){
double estimate = 1; // for starters, imagine that n's square root is 1
// if 1 is a square root, the 'other' square root will be n/1 (since the product of the roots needs to be n),
// so our new square root estimate would be the average of the two roots
double newEstimate = 0.5*(estimate + x/estimate);
double epsilon = 0.000001;
while(abs(estimate-newEstimate) > epsilon){
estimate = newEstimate;
newEstimate = 0.5*(estimate + x/estimate);
}
return estimate;
}// mySqrt()
int main() {
double s = mySqrt(5);
cout << s << endl; // expect 2.236
return 0;
}// main()
