A parameter is a value that is sent to a method when it is called.
Here is an example of a method that uses a parameter.
class CheckingAccount { . . . . private int balance; . . . . public void processDeposit( int amount ) { balance = balance + amount ; } }
The parameter amount
is used by a caller to send a
value to the method.
This is called passing a value into the method.
Here is part of a main()
method that uses the parameter to
pass a value into the processDeposit()
method of an object:
class CheckingAccountTester
{
public static void main( String[] args )
{
CheckingAccount bobsAccount = new CheckingAccount( "999", "Bob", 100 );
bobsAccount.processDeposit( 200 );
. . . . . .
}
}
When the statement
bobsAccount.processDeposit( 200 );
is executed,
the parameter amount
is given
the value 200.
Now, as the processDeposit
method executes,
that value is added to the object's instance variable balance
:
balance = balance + amount ;
Then the method finishes and control returns to main()
.
The balance
of the bobsAccount
object has
been changed.
balance
of the object
hold its value permanently?amount
of the object's method
hold its value permanently?