Calculate Angle of Line between two points - Java, C#, Python

CalcAngleofLineBetweenTwoPoints

    ==== J A V A ==================================
    /**
     * Determines the angle of a straight line drawn between point one and two. The number returned, which is a double in degrees, tells us how much we have to rotate a horizontal line clockwise for it to match the line between the two points.
     * If you prefer to deal with angles using radians instead of degrees, just change the last line to: "return Math.atan2(yDiff, xDiff);"
     */
    public static double GetAngleOfLineBetweenTwoPoints(Point.Double p1, Point.Double p2)
    {
        double xDiff = p2.x - p1.x;
        double yDiff = p2.y - p1.y;
        return Math.toDegrees(Math.atan2(yDiff, xDiff));
    }
    
    ==== C # ==================================
    /**
     * Determines the angle of a straight line drawn between point one and two. The number returned, which is a float in degrees, tells us how much we have to rotate a horizontal line clockwise for it to match the line between the two points.
     * If you prefer to deal with angles using radians instead of degrees, just change the last line to: "return Math.Atan2(yDiff, xDiff);"
     */
    public static float GetAngleOfLineBetweenTwoPoints(PointF p1, PointF p2)
    {
        float xDiff = p2.X - p1.X;
        float yDiff = p2.Y - p1.Y;
        return Math.Atan2(yDiff, xDiff) * (180 / Math.PI);
    }
    
      ==== P Y T H O N ==================================
      /**
     * Determines the angle of a straight line drawn between point one and two. The number returned, which is a double in degrees, tells us how much we have to rotate a horizontal line clockwise for it to match the line between the two points.
     * If you prefer to deal with angles using radians instead of degrees, just change the last line to: "return atan2(yDiff, xDiff)"
     */
    from math import atan2,degrees

    def GetAngleOfLineBetweenTwoPoints(p1, p2):
        xDiff = p2.x - p1.x
        yDiff = p2.y - p1.y
        return degrees(atan2(yDiff, xDiff))
        
        
    REFERENCE: WikiCode
    Available: http://wikicode.wikidot.com/get-angle-of-line-between-two-points
    
    -----------------------------------------------------------------------------
    Calc angle between two points, converging at a center(intermediary) point
    
    public static double angleBetweenTwoPointsWithFixedPoint(double point1X, double point1Y, 
        double point2X, double point2Y, 
        double fixedX, double fixedY) {
    
    double angle1 = Math.atan2(point1Y - fixedY, point1X - fixedX);
    double angle2 = Math.atan2(point2Y - fixedY, point2X - fixedX);
    
    return angle1 - angle2; 
    }
    And call it with three points (using Math.toDregrees to transform resulting angle from radians to degrees):
    
    System.out.println(Math.toDegrees(
                angleBetweenTwoPointsWithFixedPoint(0, 0, // point 1's x and y
                                                    1, 1, // point 2
                                                    1, 0  // fixed point
                                                   )));
    Output: 90.0
    
REFERENCE: StackOverflow
Available: http://stackoverflow.com/questions/26076656/calculating-angle-between-two-points-java