balancehold its value permanently?
balanceis part of the state of the object and holds its value as long as the object exists.
amounthold its value permanently?
amountis used only to pass in a value into the method. It is not permanent.
An identifier is a name used for a class, a variable, a method, or a parameter. The following definitions are useful:
amountis a formal parameter of
processDepositis called is an actual parameter.
When a method is called, the formal parameter is temporarily "bound" to the actual parameter. The method uses the formal parameter to stand for the actual value that the caller wants to be used.
For example, here
uses the formal parameter
to stand for the actual value
used in the procedure call:
balance = balance + amount ;
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.
What is used to store the state of an object?