title: What is the exact definition of instance variable?
body: <p>I think instance variables are simple data types like int or double. Everything that is created automatically when the object is created.</p>
  
  <p>If an object creates additional objects - like everything that is it done with the NEW keyword - these are not instance variables.</p>
  
  <p>Am I right or wrong? 
  What is the exact definition?</p>