Direction of a point from a line segment

DirectionLeftRightPoints.cpp

// https://www.youtube.com/watch?v=VMVuKpj_RQQ&list=PL2_aWCzGMAwLL-mEB4ef20f3iqWMGWa25&index=9 

#include <iostream>

struct Point {
    double x, y;
    Point(double x, double y)
    : x(x), y(y)
    {
    };
};

Point substract(Point N, Point A) {
    int x = N.x - A.x;
    int y = N.y - A.y;
    Point result(x, y);
    return result;
};

double crossProduct(Point A, Point B) {
    return A.x * B.y - B.x * A.y;
};

const int LEFT = -1; const int RIGHT = +1, ON_THE_LINE = 0;

int getDirection(Point A, Point B, Point P) {
    B = substract(B, A);
    P = substract(P, A);
    double result = crossProduct(B, P);
    if (result > 0) return LEFT;
    if (result < 0) return RIGHT;
    if (result == 0) return ON_THE_LINE;
    return 123; // I'll fixt it later.
};

int main() {
    Point A(-30, 10);
    Point B(29, -15);
    Point P(15, 28);
    std::cout << getDirection(A, B, P) << std::endl;
    return 0;
}