1.  Technical Field
The exemplary disclosure generally relates to a fastening structure used in a portable electronic device. 
2.  Description of Related Art
In assembling electronic devices, many subsidiary pieces need to be secured to a main housing of the electronic device.  A typical method uses screws to fasten the subsidiary piece to the main housing.  However, because most of the subsidiary pieces are thin and usually made of plastic, and due to the fragile nature of plastic, it is difficult to maintain a tight engagement between the subsidiary pieces and the main housing with screws. 
Therefore, there is room for improvement within the art.