Unit 23 - Pop Quiz

What does the following code fragment write to the monitor?

int sum = 14;

if ( sum < 20 )

System.out.print(“Under “);

else

System.out.print(“Over “);

System.out.printIn(“the limit.”);

• Under

• Over

• Under the limit

• Over the limit

Which of the following is FALSE about Event driven programming?

• Event driven programs can be run multiple times with different outcomes based on user interactions

• The flow of event driven program cannot always be known ahead of time

• Event driven programs do not implement algorithms

• Some portion of an event driven program may never execute while the program is still running

Look at the following line of code.

String operator = "?" ;

switch(operator)

{

case '+':

printf("%.1lf + %.1lf = %.1lf",firstNumber, secondNumber, firstNumber+secondNumber);

break;

case '-':

printf("%.1lf - %.1lf = %.1lf",firstNumber, secondNumber, firstNumber-secondNumber);

break;

default:

printf("Error! operator is not correct");

}

Which case will be executed?

• Case +

• Case *

• Default case

• All the cases

What role does the "break" keyword play?

• exits the program

• exits the construct

• exits the application

• exits the operating system

OOP organizes a software into classes and objects. What exactly are objects?

• Objects are subclasses

• Objects are instances of classes

• Objects are data types

• Objects are constructors

How is data abstraction achieved in Java?

• By using abstract keyword

• By using private and public keywords

• By using extend keywords

• By using string keyword

Which of the following is a looping construct?

• Switch Case

• If Else

• do while

• JOptionPane

One of the following statements is false. Which one is it?

• Event handlers are a response to a computer event

• Events can be easily predicted and testing event driven programs is very easy

• Graphic User Interface can easily be programmed using event driven programming

• Their can be timed events as well that trigger the OS based on system clock

Encapsulation, one of the fundamentals of object oriented programming, means...

• Variables and Methods are kept in separate blocks

• wrapping the data (variables) and code acting on the data (methods) together as a single unit

• hiding data by using private or public keyword

• objects are instances of classes

JOptionPane is a...

• Class that provides methods to create pop up messages

• Object of JFrame Form

• Instance of Helloworld Java Application

• All of the above