iwoty/oop-geometry

The story

Do you love geometry? Our young friend Zigy (Zygfryd) loves it too. Unfortunately it's one-sided love. He's studying hard for his high-school exam, but with minor success. You've got to help him!

But how?

You'll write a Object Oriented Python Application to teach him geometry. Don't worry! Our Finnish software architect Linus Coolvalds has already created a boilerplate for you. However he forgot to create a UML class diagram. You have to do it for him.

Requirements

In order to help Zigy you have to:

• Implement 6 classes in geometry.py module
• Implement main.py module.
• You are allowed to implement your own modules. Remember about clean code.
• Explain why Linus designed some methods to be class methods instead of instance methods.
• Remember about comments and docstrings.
• Add UML.png file containing UML class diagram of a geometry.py module
• All tests must pass.
• Focus most on the OOP not the ui.

Hint: you can reuse code from the previous assignments.

Specifications

Here you can find information what you have to implement.

main.py

This is the main entrance of the program.
The program allows user to create and add shapes to a list and do some things with it.

Running python main.py should show such menu:

Learn Geometry.
  What do you want to do?
  (1) Add new shape
  (2) Show all shapes
  (3) Show shape with the largest perimeter
  (4) Show shape with the largest area
  (5) Show formulas
  (0) Exit program

Features

As you can see the program has 5 features.

1. Add new shape

This feature allows user to add new shape to shapes list. User should be able to choose what kind of shapes he/she wants to add. Then he/she should specify attributes that a given shape requires.

2. Show all shapes

This feature should print table containing all shapes added to the list. Take a look at ShapeList.get_shapes_table()

3. Show shape with the largest perimeter

This feature prints shape with the largest perimeter from a list.

4. Show shape with the largest area

This feature prints shape with the largest area from a list.

5. Show formulas

This feature should allow user to choose shape type and print it's formulas (perimeter, area).

Classes

This is the most important part of this assignment. You've got to implement all of them in geometry.py module.

Shape Class

This is a so called abstract class. It means that we don't create instances of it. We only use it as a parent class for other concrete classes. This parent is a boilerplate for it's children. It contains attributes and methods that should be implemented in child classes.

Instance methods

__init__(self)

Constructs shape object. Should raise ValueError if any of the parameters is below 0 (e.g. circle with negative radius doesn't exist).

get_area(self)

Returns the area of the shape.

get_perimeter(self)

Returns the perimeter of the shape.

__str__(self)

Returns information about given shape as string.

Class methods

get_area_formula(cls)

Returns formula for the area of the shape as a string.

get_perimeter_formula(cls)

Returns formula for the perimeter of the shape.

Why this methods should be class methods? Edit this readme and give answer below:
Cause they are corresponding to all of the child classes.

Circle Class

This class represents circle shape.

Parent class

Shape

Attributes

• r
  • data: float
  • description: circle radius length

Methods

__init__(self, r) - constructor of the Cricle

Override (implement) other methods inherited from the parent class.
Required formulas: Perimeter = 2×π×r Area = π×r²

Triangle Class

This class represents triangle shape.

Parent class

Shape

Attributes

• a
  • data: float
  • description: one side's length of a triangle
• b
  • data: float
  • description: second side's length of a triangle
• c
  • data: float
  • description: third side's length of a triangle

Methods

__init__(self, a, b, c) - constructor of the Triangle

Override (implement) methods inherited from the parent class.
Required formulas:
Perimeter = a + b + c
Area = sqrt(s(s-a)(s-b)(s-c)),
          where s = (a+b+c)/2
^{Heron's Formula}

Equilateral triangle Class

This is a triangle that has all sides equal.

Parent class

Triangle

Attributes

Hint: check if you can reuse attributes from the parent class

• a
  • data: float
  • description: side's length of a triangle

Methods

__init__(self, a) - constructor of the Equilateral Triangle

Decide on your own if you have to override inherited methods.

Rectangle Class

This class represents rectangle shape.

Parent class

Shape

Attributes

• a
  • data: float
  • description: one side length
• b
  • data: float
  • description: second side length

Methods

__init__(self, a, b) - constructor of the Rectangle

Override (implement) other methods inherited from the parent class.
Required formulas:
Perimeter = 2a + 2b
Area = a×b

Square Class

This is a rectangle that has all sides equal.

Parent class

Rectangle

Attributes

Hint: check if you can reuse attributes from the parent class

• a
  • data: float
  • description: side's length of the square

Methods

__init__(self, a) - constructor of the Square

Decide on your own if you have to override inherited methods.

Regular pentagon Class

This is a shape with 5 sides. All sides are of the same length.

Parent class

Shape

Attributes

• a
  • data: float
  • description: side's length of the pentagon

Methods

__init__(self, a) - constructor of the RegularPentagon

Override (implement) other methods inherited from the parent class.
Required formulas:
Perimeter = 5a
Area = (a² sqrt(5(5+2sqrt(5))))/4 (see image above)

ShapeList Class

This class is meant to hold geometrical shapes (objects that inherit from Shape class).

Attributes

• shapes
  • data: list
  • description: list of Shape objects

Methods

__init__(self)

Constructs ShapeList object

add_shape(self, shape)

Adds shape to shapes list. This method should check if shape's has Shape class as it's ancestor. If not it should raise TypeError. Hint: check isinstance function. (This is a good example of so called polymorphism)

Arguments

• shape
  • data_type: Shape
  • description: object to be added to the shapes list

get_shapes_table(self)

This method returns shapes list as string formatted into table. This is sample output:

 /------------------------------------------------------------------------------------------------------\
 |  idx   |       Class    |       __str__        |   Perimeter  |   Formula   |   Area    |  Formula   |
 |--------|----------------|----------------------|--------------|-------------|-----------|------------|
 |   0    |      Circle    |    Circle, r = 3     |     18.85    |     2×π×r   |   28.27   |   π×r^2    |
 |--------|----------------|----------------------|--------------|-------------|-----------|------------|
 |   1    |      Square    |    Square, a = 2     |      8.00    |      4×a    |    4.00   |    a^2     |
 \------------------------------------------------------------------------------------------------------/

Return value

string object

get_largest_shape_by_perimeter(self)

Returns shape with largest perimeter. Hint: have a look at comparison methods

Return value

Shape object

get_largest_shape_by_area(self)

Returns shape with largest area. Hint: have a look at comparison methods

Return value

Shape object

Extra

If you've fulfilled all the basic requirements and you're ambitious enough to continue, here's idea what you can do.

Help Zigy even more and implement quiz feature. This feature should generate random shape. Tell the user the type of shape and it's attributes. The user should calculate the perimeter and area. The program should check users answer.

Visualize shapes using turtle module.

You can also add more shapes to the geometry class.