How to turn an object around and move into the opposite direction?

How to turn an object around and move into the opposite direction?

Considering out of bounds position is 6 and -6.
I want to make the ship turn around and move in the opposite direction.
This is the code I have.. It is still not working 100% how I want it. I am
curious to see if anyone had any ideas how do improve. Here is the logic
of my code.
//If the ship hits a boundary it turns around and moves in
the opp.
//direction. To do this, the ship's velocty should be
flipped from a
//negative into a positive number, or from pos to neg if
boundary
//is hit.
//if ship position is -5 at velocity -1 new ship pos is -6
//if ship position is -6 at velocity -1 new ship velocity
is +1
// new ship position
is +5
Here is my code:
public void move()
{
position = velocity + position;
if (position > 5)
{
velocity = -velocity;
}
else if (position < -5)
{
velocity = +velocity;
}
}