18.   Write a top-down design for the following tasks.

a.   Calculating the average of ten test scores

b.   Calculating the average of an unknown number of test scores

c.   Describe the differences in the two designs.

19.   Write a top-down design for the following tasks.

a.   Finding a telephone number in the phone book

b.   Finding a telephone number on the Internet

c.   Finding a telephone number on a scrap of paper that you have lost

d.   Describe the similarities and differences among these designs.

20.   Distinguish between information and data.

21.   Write a top-down design for sorting a list of names into alphabetical order.

22.   a. Why is information hiding important?

b. Name three examples of information hiding that you encounter every day.

23.   An airplane is a complex system.

a.   Give an abstraction of an airplane from the view of a pilot.

b.   Give an abstraction of an airplane from the view of a passenger.

c.   Give an abstraction of an airplane from the view of the cabin crew.

d.   Give an abstraction of an airplane from the view of a maintenance mechanic.

e.   Give an abstraction of an airplane from the view from the airline’s corporate office.