CS 535 Object-Oriented Programming
Fall Semester, 2003
© 2003, All Rights Reserved, SDSU & Roger Whitney
San Diego State University -- This page last updated 09-Oct-03
Create a BinaryTreeKeyNotFoundError exception. Make the exception resumable.
Implement a BinarySearchTree class. In some implementations people use at least
two classes, a Node class and a BinarySearchTree class. The requirements of
this problem are small enough that one class will be enough. Make the class a
subclass of Collection. Each node in your tree contains a key and a value. This
makes the tree act like a dictionary. The keys must be objects that respond to
the operations <, >, <=, >=. In any single tree all the key have to
be comparable with each other. Insuring that this is the case is the
responsibility of the user of your code. The key orders the nodes in your tree.
The tree does not have to be balanced. You must implement the following methods:
aBlock – Evaluates the block with the value from each node in the tree.
– returns the number of nodes in the tree
aKey – returns the value at the node with the given key. Raises
BinaryTreeKeyNotFoundError if the key is not in the tree.
aKey ifAbsent: aBlock - returns the value at the node with the given key.
Evaluate aBlock if the key is not in the tree.
aKey put: anObject – Adds a new node to the tree with aKey is key and
anObject as the value. The node is of course placed in the correct location in
it is possible to implement a binary search tree using an array or ordered
collection (or various other collections) this is not allowed in this
assignment. Nor are you allowed to keep a parallel structure of the tree in
another collection. You are to implement your own do: method without using the
do: of another collection class.
Write SUnit tests for the methods in problem 2.
Smalltalk code that reads a file named ‘start’ and copies the
contents to a file name ‘end’ and replaces each comma ($,) with a
period ($.). So if start contains:
will end up with:
streams to parse the file rather than using a replace on a string.
5. Let ‘data’ be a file that contains rows of numbers. In each row the numbers are separated by commas. Write Smalltak code that reads the file ‘data’, sums the numbers in each row, and writes out the row sums in a file called ‘result’. Each row sum in on a separate row in the file result. So if data contained:
result would contain:
Create an HtmlTable class and SUnit tests for it. An HtmlTable object holds an
N*K matrix of strings. The class needs to have the following operations:
HtmlTable class>>rows: numberOfRows columns: numberOfColumns
Returns an HtmlTable object that has the given number of rows and columns.
HtmlTable>>row: rowIndex column: columnIndex
Returns the string in the given location
HtmlTable>>row: rowIndex column: columnIndex put: aString
Puts aString in the given location.
Returns a string containing the html representation of the table.
| table |
table := HtmlTable rows: 2 columns: 2.
row: 1 column:1 put: ‘hi’;
row: 1 column: 2 put: ‘mom’;
row: 2 column: 1 put: ‘how’;
row: 2 column: 2 put: ‘are you’.
last statement will return the string
<td>how</td> <td>are you</td>
might find the method CharacterArray>>match: useful in your unit test(s).
7. Create a WordStream class a subclass of ReadStream. The next method of the
WordStream is to return the next word in the stream. Words are separated by
space, tab, carriage return, line feed, null, form feed, period (.), comma (,)
, semicolon (;), question mark (?), single quite (‘), double quote
(“) or the exclamation point (!). Do not return the separators. The
following test shows the behavior of WordStream. Provide a better unit test.
| word |
word:= WordStream on: 'cat dog,,mom'.
assert: word next = 'cat';
assert: word next = 'dog';
assert: word next = 'mom';
assert: word next = nil
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