Author Question: Virtual Private Networks are hardware or software that controls access between networks. Indicate ... (Read 817 times)

Marty

  • Hero Member
  • *****
  • Posts: 553
Virtual Private Networks are hardware or software that controls access between networks.
 
  Indicate whether the statement is true or false

Question 2

Describe the difference between concrete and abstract classes and give an example for each.
 
  What will be an ideal response?



smrtceo

  • Sr. Member
  • ****
  • Posts: 344
Answer to Question 1

FALSE

Answer to Question 2

An abstract class is one that cannot have instances, while a concrete class can. If a class has all the required attributes and operations that we expect from an object, then it is concrete. If it has only a subset, then it is abstract and we need a more specialized class. For example Art is an abstract class because we have found it to be too general to satisfactorily represent a specific work of art. Saying that somebody is interested in art does not explain enough. At best, it prompts a question: what kind of art? The answer might be music, literature, painting, theatre, etc. On the other hand, the Literature class has enough attributes to be concrete. That is, we believe it can properly represent an actual literary work.



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question


 

Did you know?

The use of salicylates dates back 2,500 years to Hippocrates's recommendation of willow bark (from which a salicylate is derived) as an aid to the pains of childbirth. However, overdosage of salicylates can harm body fluids, electrolytes, the CNS, the GI tract, the ears, the lungs, the blood, the liver, and the kidneys and cause coma or death.

Did you know?

Once thought to have neurofibromatosis, Joseph Merrick (also known as "the elephant man") is now, in retrospect, thought by clinical experts to have had Proteus syndrome. This endocrine disease causes continued and abnormal growth of the bones, muscles, skin, and so on and can become completely debilitating with severe deformities occurring anywhere on the body.

Did you know?

Egg cells are about the size of a grain of sand. They are formed inside of a female's ovaries before she is even born.

Did you know?

Your skin wrinkles if you stay in the bathtub a long time because the outermost layer of skin (which consists of dead keratin) swells when it absorbs water. It is tightly attached to the skin below it, so it compensates for the increased area by wrinkling. This happens to the hands and feet because they have the thickest layer of dead keratin cells.

Did you know?

Many people have small pouches in their colons that bulge outward through weak spots. Each pouch is called a diverticulum. About 10% of Americans older than age 40 years have diverticulosis, which, when the pouches become infected or inflamed, is called diverticulitis. The main cause of diverticular disease is a low-fiber diet.

For a complete list of videos, visit our video library