sqrt.cxx

float root(float n, float epsilon=.000001f)
{
    if (n <= 0.0f) 
        return 0.0f;
    
    float guess = n/2.1f;
    float error = n - guess*guess;
    while (epsilon < fabs(error))
    {
        guess += error / 2;
        error = n - guess*guess;
    }
    return guess;
}

int main()
{
    float n = 2;
    float a = sqrt(n);
    float b = root(n, e);
    fprintf(stdout, "sqrt(%f) = %2.9f\n", n, a);
    fprintf(stdout, "root(%f) = %2.9f (precision: %2.9f)\n", n, b, e);
    fprintf(stdout, "delta: %2.9f, epsilon: %2.9f\n", fabs(b-a), e);

    return 1;
}

newton > babylon