balance
hold a permanent value?
balance
is part of the state of the object and will hold a
value as long as the object exists.amount
hold a permanent value?
amount
is used only to pass in a value to the method.
It does not have a permanent existance.The following definitions are useful:
amount
is a
formal parameter of processDeposit
200
used when processDeposit
is called is an actual parameter.
When a method is called,
the formal parameter is temporarily "bound" to the actual parameter.
The method can then use a name to stand for the actual value that the caller
wanted to be used.
For example, this statement from a method
uses the parameter amount
to stand for the actual value
used in the procedure call:
balance = balance + amount ;
Important Note: formal parameters are bound to an actual value only as long as their method is active. When a method returns to its caller, the formal parameters no longer contain any values. They cannot be used to store the state of an object.