Passing Parameter in Methods

Definition:

• Parameter: the variables in the method header.
  It looks like a port on the computer for you to insert a USB drive or
  the hole on the COKE machine for you to insert coins.
• Argument: the information attached from caller.
  It looks like the USB drive for you to insert to a computer or
  the coins to use to insert to machine.
  
• pass by value:
  The parameter & argument are located at the different memory spaces.
  You copy the value of argument to parameter.
• pass by reference:
  The parameter & argument locate at the same spot.
  For example, Pass an array to a method.