iOS Programming: The Big Nerd Ranch Guide

Using Instances

To use an instance of a class, you must have a variable that points to that object. A pointer variable stores the location of an object in memory, not the object itself. (It “points to” the object.) A variable that points to a Party object is declared like this:

P​a​r​t​y​ ​*​p​a​r​t​y​I​n​s​t​a​n​c​e​;​

Creating this pointer does not create a Party object – only a variable that can point to a Party object.

This variable is named partyInstance. Notice that this variable’s name does not start with an underscore; it is not an instance variable. It is meant to be a pointer to an instance of Party.

Creating objects

An object has a life span: it is created, sent messages, and then destroyed when it is no longer ...