sqrt_a

#include<iostream>
#include<cmath>
double sqrt_a(double a, double eps) {
    int xk[100];
    xk[1] = a;
    int  i = 2;
    for (; abs(xk[i] - xk[i - 1]) < eps; i++)
    {
        xk[i] = 1 / 2 * (xk[i - 1] + (a / xk[i - 1]));
    }
    return abs(xk[i] - xk[i - 1]);
}