Final and Static Keywords

Creating constants  There will be occasions where data items in a program have values that do not change.  Maximum score in an exam (100)  The number of hours in a day (24)  The mathematical value of pie ( )  Do the values of these variables vary?

Constants  Values that remain constant throughout a program (as opposed to variable) should be named and declared as constants  Constants are declared like variables in Java except that they are preceded by the keyword final final int HOURS =24

Changing the Value  Any attempt to change this value later in the program will result in a compile error. For example: final int HOURS =24 //create constant HOURS = 12 //will not compile!

The static keyword  You might already have noticed the keyword static in front of the names of methods or attributes in some Java classes  Static means that when any object in the class changes the value of the variable, that value changes for all objects in the class  An attribute declared as static, will, if changed, change for all objects in the class

The static keyword  Class BankAccount2 Private static double interestRate; Private void setInterestRate (double rateIn) { interestRate = rateIn: } double getInterestRate() { return InterestRate; }Phil.setInterestRate(5.2)Phil.getInterestRate()

Exam Topics

Topics  Java Basics  Primitive Data Types and Variables  Expressions and Operators –Relational Operators –Arithmetic Operators  Program Control –If statements –If else statements –Multiple Else if statements –Nested If Statements –Switch statements

Topics  Program Control –For loops –While loops –Do while loops  Classes and Objects  Methods  Getter and Setter Methods  Constructors  Access Protection and Visibility Modifiers  Polymorphism –Overloading –Overriding

Topics  Inheritance  Final and Static

In Class Exam  Students have 45 minutes to complete the exam  40 MCQ Questions  Students will be awarded: –3 Marks for every correct answer –1 Mark will be deducted for each incorrect answer

Inclass Exam  Please ensure to indicate your selected in both the boxes on this answersheet AND the EDPACK sheet  In cases of discrepancies the answer indicated on the EDPACK sheet will be taken as the given answer  Please ensure to use a pencil when populating the EDPACK sheet  BRING A PENCIL  Both this answerbook and the EDPACK sheet must be submitted.