M206 Computing: An Object-oriented Approach

Smalltalk Exercises - Collections

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Question 1
The following creates a set of Chelsea footballers:

blues := Set new.
blues add: 'Ferreira';
      add: 'Terry';
      add: 'Tiago';
      add: 'Lampard';
      add: 'Robben';
      add: 'Carvalho'

A set of Portugese footballers is also created with:

portugal := Set new.
portugal add: 'Costinha ';
         add: 'Ferreira';
         add: 'Rui Costa';
         add: 'Tiago';
         add: 'Figo';
         add: 'Deco';
         add: 'Carvalho'

By using just the two variables and one message in the protocol of Set, write a simple expression that will return a set representing those Portugese footballers that play for Chelsea.

Question 2
(i) What is the textual representation of this set?
(ii) What is the textual representation of this set when it receives the printString message?

Question 3
The following code is used to create a set:

mountainSet := Set new.
mountainSet add: 'Matterhorn';
add: 'Everest';
add: 'K2'

Explain the consequences of evaluating the following expression:
mountainSet remove: 'Ben Nevis'

Question 4
Write an expression that will check the set referenced by mountainSet for the presence of the string 'Ben Nevis'. If the string is not present the user is notified by means of a dialogue box.

Question 5
Write a simple expression that will open dialogue boxes displaying all the elements in mountainSet.

Question 6
What class of object does deadPoets reference after evaluating the following?

deadPoets := Set new add: 'Milton';
add: 'Shakespeare';
add: 'Keats'

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John McSweeney

OU Courses

Smalltalk Exercises

May 12, 2008, 1:36 pm

M206 Computing: An Object-oriented Approach

Smalltalk Exercises - Collections