Greenfoot Ch 1-4 (Version 2)

A boolean return data type gives us a true false return.

• True

• False

Single line comment tags are written with ____

This kind of comment tag is used for what kind of comments? //

• Group

• Single line

Constructors are sometimes used to initialize instance variables – especially if they represent objects.

• True

• False

The code that a programmer writes is called _______________ code.

This kind of comment tag is used for what kind of comments? /* */

• Single line

• Group

It may be accessed directly by any code outside the class and it is inherited by subclasses.

• Private

• Protected

• Public

Attempt to always use local variables except when the variable exhibits a natural “has-a” relationship to the object For Example:  A car has a make, model, type, color

• True

• False

How does Step differ from Step into?

• Step steps over methods, Step Into steps into methods

• Step steps into methods, Step Into steps over methods

  Methods that belong to classes (as opposed to objects) are marked with the keyword static in their signature.

• True

• False

When a method returns nothing this special word is used for the return type:

To pass additional data to a method we specify a

• Name

• Return type

• Parameter

• Parenthesis

_________: - Translate source code into byte code which the Java Interpreter (JVM- Java Virtual Machine) can understand.

How would you call or invoke the following method? public void move()   {       setLocation(getX() + 5, getY();   }

• Public void move();

• Move()

• Move();

Using a dot between a class name and a method name is called ____ ____.

A constructor must be called to create an object

• True

• False

In object-oriented programming a method is

• A design technique for creating classes

• A disciplined way of writing programs

• An approach developed by the great Stanislawski

• A process for instantiating an object

• Code that allows access to an object's attributes or that carries out some other action for the object.

Calling this kind of method is like a command.

• Int

• Boolean

• Void

This is a valid constructor public Elephant()     {         imageDown = new GreenfootImage("elephant.png");         imageUp = new GreenfootImage("elephant2.png");         setImage(imageDown);     }

• True

• False

It is good naming convention to  name a class in Greenfoot “crab” .

• True

• False

Strings are indicated with double quotes.

• False

• True

Given the following constructor, what is the correct way to add an elephant object from this constructor at coordinates, 50,50? public Elephant()     {         imageDown = new GreenfootImage("elephant.png");         imageUp = new GreenfootImage("elephant2.png");         setImage(imageDown);     }

• Elephant();

• New Elephant()

• This is an invalid constructor.

• AddObject(new Elephant(), 50,50)

You may not be accessed directly by any code outside the class (can’t get to it with the ‘.’)  and is not inherited by subclasses.

• Private

• Protected

• Public

This kind of error compiles but the data that comes out is wrong.  For example, you want your balloons to move up but they go to the right.

The return type of a method

• Specifies the number of items a method returns

• Specifies what a method call will return

• Specifies the type of data that a method will accept.

• Is always void

Call the turn method from the given method. public void turn (int angle) {        setRotation(getRotation() + angle);  }

• Turn(45);

• Public void turn (45);

• Turn(45)

• Public void turn (45)

Public void move()  - This part of the method is called the ________________________. { }

A compiler

• Maintains a collection of programs

• Tests a program's logic

• Translates source code into executable code

• Translates executable code to machine code

The general "if statement"  format it is if ( _______________ ) {     statements to execute }

• Boolean statement

• Condition

• Statements

_____________ classes have subclasses.  Choose the best answer.

• Crab

• Super

• Actor

• World

Reasons for using comment tags

• Describe your code so other programmers can follow it

• Help document your code so you can follow it

• Trouble shoot your code by commenting out sections of code

What class is this method from? static int getRandomNumber(int limit)

In object-oriented programming a class is

• A group of people sharing the same relationship to the means of production.

• The term used for programs

• A model or template from which objects are created

• A grouping of users sharing common objectives

• A procedure for a calculation inside a program.

How would I write a random number that would show numbers from 1 to 8?

• Greenfoot.getRandomNumber(8) + 1;

• Greenfoot.getRandomNumber(8);

• Greenfoot.getRandomNumber(1) + 8;

Which are correct ways to indicate 25%

• GetRandomNumber(100) < 25

• GetRandomNumber(4) < 1

• GetRandomNumber(16) < 4

Write a method call that will return a random integer between 0 and 10.                                         

• Greenfoot.getRandomNumber(10)< 1;

• Greenfoot.getRandomNumber(100) < 10;

• Greenfoot.getRandomNumber(10);

• Greenfoot.getRandomNumber(10)+1;

Write an if statement that tells an object to turn  17 degrees,  but only 31 percent of the time.

• If (Greenfoot.getRandomNumber(100) <31); turn(17);

• If (Greenfoot.getRandomNumber(100) <31) turn(17);

• If Greenfoot.getRandomNumber(100) <31 turn(17);

An instance variable is sometimes called a ________

This statement  tells an object to turn a random number of degrees between -20 and 20.        Greenfoot.getRandomNumber(-20, 20);

• True

• False

Changing the flow of control in a program to jump to some pre-written code is known as ___________________ a method.

Given an integer variable  drivingAge that has already been declared, write a statement that assigns the value  17 to  drivingAge . So, after your code is executed, the variable drivingAge, will have the value  17.

Common characteristics of a constructor’s signature

• Same name as the class

• No return type

• Public modifier

A method is written in this format.

It may not be accessed directly by any code outside the class (can’t get to it with the ‘.’) and it is inherited by subclasses.

• Private

• Protected

• Public

An example of this kind of error would be missing ( )  on a method.

When an object has an "is a" relationship with another object, that relationship is called ____________

This is a valid constructor public  void AnimalWorld()     {            // Create a new world with 400x300 cells         // with a cell size of 1x1 pixels.         super(400, 300, 1);     }

• True

• False

What is the formal name for the process of creating an object from a class?