Chapter 9.5, Problem 25SC

Program Plan Intro

The “instanceof” operator:

• The “instanceof” operator tests whether an object belongs to a particular type.
• For example,

  //use of instance of operator

  obj instanceof Question

• The above statement returns “true” if the type of “obj” is convertible to “Question”.
• This happens if “obj” refers to an actual class “Question” or to a subclass such as “ChoiceQuestion”.

Class “Object”:

• The “Object” is the root class of library of java.
• By default, the class “Object” is the base class of all other java classes.
• Every class is subclass of class “Object”.