function print 0 all the time?

[DrJones]

I am trying write a simple function that outputs the standard deviation of a cloud of points, but for some dumb reason it keeps outputting, 0.. Why?


Here is the code..

bool std_dev(vector<Point2f> points)
{
    double Std_dev;
    Point2f mean = Mean(points);
    for(int i = 0; i < points.size(); i++)
    {    
        Std_dev += pow(euclideanDistance(points[i]-mean),2);

    }
    //cout << "Std_dev: "<< Std_dev << endl; 
    Std_dev = Std_dev*(1/points.size());
    Std_dev = sqrt(Std_dev);
    cout << "Std_dev: "<< Std_dev << endl; 
    return true; //Threshold has to be added to know when it should re init the goodFeaturesToTrack Function. 
}

double euclideanDistance(Point2f point1)
{
    double match=0;
    match += sqrt((point1.x - 0) * (point1.x - 0)+ (point1.y - 0) * (point1.y - 0));
    //cout << "eucliadian distance: " << match << endl; 
    return match;
    

[ne555]

> Std_dev = Std_dev*(1/points.size());
integer division returns an integer