Description
1 Point (30 points)
State a class Point that has two instance variables, its rational coordinates self.x
and self.y.
• Implement in this class a constructor with two arguments, the values of the
coordinates. Each argument should have a default value 0.0, allowing to call
this method without arguments.
• Write two methods named getX and getY that respecitvely return the value
of self.x and the value of self.y.
• Write a method named setX that takes a rational value as argument and
modifies self.x so as it becomes equal to this value.
• Write a method named setY that takes a rational value as argument and
modifies self.y so as it becomes equal to this value.
• Write a method named toString that returns a string containing the two
coordinates of the point self, within parenthesis and separated by a comma.
• Write a method named equals that takes another object of class Point as
argument and returns True if the x and y coordinates of this points are equal
to the x and y coordinates of self, and returns False otherwise.
Outside from the class, write the following statements: Create a point p1 of coordinates (0, 0) and un point p2 of coordinates (1, 2). Print out the coordinates of
the two points on the same line, by calling toString on the two points. Print the
result of applying the method equals on point p1, using p2 as argument. Set the x
coordinate of p2 equal to the x coordinate of p1, using the methods setX and getX.
Set the y coordinate of p2 equal to the y coordinate of p1, using the method setY
and getY. Print again the result of applying the method equals on point p1, using
p2 as argument. Increment by 1 the x coordinate of p2, using the methods setX and
getX . Print again the result of applying the method equals on point p1, using p2
as argument.
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2 Rectangle (30 points)
State a class Rectangle that has three instance variables: a point (an object of the
class Point previously defined, corresponding to the left bottom corner), a rational
width and a rational height.
• Implement in this class a constructor with three arguments, a point and two
rational values, to be assigned to the three instance variables. No default values
should be stated (the constructor must be called with three arguments).
• Write a method named perimeter that returns the perimeter of the rectangle.
• Write a method named area that returns the area of the rectangle.
• Write a method named getOrigin that returns a reference to the point representing the left bottom corner of the rectangle.
• Write a method named toString that returns a string containing, on the same
line, the string representing the bottom left corner, followed by the rectangle
width and height, formatted as follows (the values will differ depending on
each object):
(0.0,0.0), L=2, H=5.5.
Outside from the class, write the following statements: Create a rectangle r1 whose
bottom left corner is p1, width is 2 and height is 5.5. Create a rectangle r2 whose
bottom left corner is p2, width is 3 and height is 6. Print out the bottom left corner
of r1 and the perimeter of r1, by calling the appropriate methods. Print out the
bottom left corner of r2 and the area of r2, by calling the appropriate methods.
Print the result of the call to the method toString respectively applied to the two
rectangles r1 and r2.
3 Movable rectangle (40 points)
State a class MovableRectangle that inherits from class Rectangle. This class has
a supplementary instance variable, assumed to be boolean, called self.move.
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• Implement in this class a constructor with three arguments, a point and two
rational values, to be assigned to the three instance variables. self.move is
initially always set to False. Your code MUST call the constructor of the
superclass.
• Write a method named unlock that sets self.move to True.
• Write a method named lock that sets self.move to False.
• Write a method named moveTo that takes an object of class Point as argument,
and: If the rectangle is unlocked, moves it so as its new bottom left is the
point given as argument. Otherwise, the method prints the following message:
Warning: locked.
• Write a method named toString that returns a string containing, on the same
line, the string representing the bottom left corner, followed by the rectangle
width and height, followed by the current status (locked or unlocked) formatted
as follows (the values will differ depending on each object):
(5,15), W=2, H=2, Movable? True
(if it is locked, the end of string should be …Movable? False).
Outside from the class, write the following statements: Create a movable rectangle
r3 whose bottom left corner is p1, width is 2 and height is 2. Print the rectangle r3,
using toString. Create a point p3 of coordinates (5, 15). Call the method moveTo
on rectangle r3 in order to try moving its origin to p3. Print again the rectangle r3,
using toString. Unlock r3. Call again the method moveTo on rectangle r3 in order
to try moving its origin to p3. Print again the rectangle r3, using toString.
4 Extra-credit : Read File (5 points)
Create a class Tour with a single instance variable self.MyList that will refer to
a list object. Create a constructor that takes one string parameter, the name of a
file, filename. This class deals with files representing sets of cities. You will find
on the course website some data files tourX.csv, where X is the number of cities in
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the set. If you open such a file with a text editor, you will see that the file states
one city per row: name, x coordinate, y coordinate. The constructor must assign
the instance variable self.MyList using the file whose name is given as argument
(string parameter filename, assumed to be one of the files tourX.csv). When
called, the argument is directly a file name, not a path. The constructor assigns to
self.MyList a list of the following form (the above text is just an example used to
show the expected format):
[[’Atlanta’, ’22’, ’3’], [’Augusta’, ’46’, ’28’], . . .]
Note: in such a list [[’Atlanta’, ’22’, ’3’], [’Augusta’, ’46’, ’28’],
. . .], all elements in sublists are strings (not integers).
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