Angle conversion problems

Hi folks,

when I’d like to know the angle between two vectors, sometimes I get negative values (radian or degree). How do you convert them so I always get positive values?

Flash seems to have a strange system for calculating angles. I used the following code for doing this, but sometimes I get negative values. Please - can someone help me with this problem?

public function rangedAngleBetween(otherVector:EuclideanVector):Number
    var firstAngle:Number;
    var secondAngle:Number;
    var angle:Number;
    firstAngle = Math.atan2(otherVector.position.y, otherVector.position.x);
    secondAngle = Math.atan2(position.y, position.x);
    angle = secondAngle - firstAngle;
    while (angle > Math.PI)
        angle -= Math.PI * 2;
    while (angle < -Math.PI)
        angle += Math.PI * 2;
    return angle;