Introduction

Content

Apply

Reflect

Extend

 Variables can change

By their nature, a variable can change its value. A variable declared for referring to an object of a certain class can refer to any objects of that class. So such a variable might at one point be referring to one object, and at another point be referring to a different object.

For example:

// object variable declaration

BankAccount accountToBalance;

...

accountToBalance = account1;

display( accountToBalance.getBalance() );

accountToBalance = account2;

display( accountToBalance.getBalance() );

So at one point during the execution of these statements, variable accountToBalance was referring to the same object as account1, and in a later statement accountToBalance was referring to a different object, the one referred to by account2.

This illustrates:

• a variable can refer to different objects at different times
• two (or more) variables can refer to the same object

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