OOP Biweekly Test#1 - BS3.3

What does Moore's law predict?

A precondition is a

A class is a

A contract is a

(Check all that apply)

Assume, you have a feature defined as below:

my_feature (x: INTEGER) -- Line 01
require -- Line 02
validity_check: x >10 -- Line 03
do -- Line 04
…
end -- Line 05

What will happen if you remove line #02?

With respect to Design by Contract, when may a contract be violated?

Assume we have feature 'f (x : INTEGER)' that requires the argument x to be a non-negative number.

How can be classified precondition 'pre1'?

f (x: INTEGER)

require
pre1: x > -10

Assume we have feature 'f : INTEGER' that ensures returning a non-negative number.

How can be classified the postcondition 'post1' ?

f: INTEGER

ensure
post1: Result > -10

Which of the following statements are true about deferred classes? (select all that apply)

A key for establishing loop’s correctness is

If you were asked to design and implement two classes representing geometric figures - Circle and Ellipse, how would you use inheritance?

Check all that apply.

The precondition of a redefined feature can only stay the same or be strengthened

A class invariant in an descendant class can only stay the same or be strengthened

If you want to keep an inherited precondition, postcondition or class invariant, all you need to do is:

What are the pillars of OOP?

Assuming that PUBLIC_TRANSPORT class is descendant from TRANSPORT class.

t : TRANSPORT

tram : PUBLIC_TRANSPORT

t := tram

Which of the following statements are correct after the assignment, (select all that apply)

What is the basic type property in Eiffel?

Assume a program with three classes: A, B and C.

class
A
feature
do_work
do
print("A")
end
end

class B
inherit A redefine do_work end
feature
do_work
do
print("B")
end
end

class
C
create make
feature
make
local
a:A
b:B
do
create a
create b

a:=b

a.do_work
b.do_work
end
end

What would be the output of the program?

Assume a program with three classes: A, B and C.

class
A
feature
do_work (a:B)
do
print("A")
end
end

class B
inherit A redefine do_work end
feature
do_work(b:A)
do
print("B")
end
end


class C
create make
feature
make

local
a:A
b:B
do
create a
create b

a.do_work(b)
b.do_work(b)
end

end