0x08-python-more_classes

Python More Classes

In this project, I continued to practice object-oriented programming in Python. I learned about class methods, static methods, class vs instance attributes, andbhow to use the special __str__ and __repr__ methods.

Tasks

• 0. Simple rectangle
• 0-rectangle.py: Empty Python class that defines a rectangle.

• 1. Real definition of a rectangle
• 1-rectangle.py: Python class that defines a rectangle. Builds on 0-rectangle.py with:
• Private instance attribute width.
• Property getter def width(self): to get width.
• Property setter def width(self, value): to set width.
• Private instance attribute height.
• Property getter def height(self): to get height.
• Property setter def height(self, value): to set height.
• Instantiation with optional width and height: def __init(self, width=0, height=0):.
• If either of width or height is not an integer, a TypeError is raised with the message width must be an integer or height must be an integer.
• If either of width or height is less than 0, a ValueError is raised with the message width must be >= 0 or height must be >= 0.


• 2. Area and Perimeter
• 2-rectangle.py: Python class that defines a rectangle. Builds on 1-rectangle.py with:
• Public instance method def area(self): that returns the area of the rectangle.
• Public instance attribute def perimeter(self): that returns the permiter of the rectangle (if either of width or height equals 0, the perimeter is 0).


• 3. String representation
• 3-rectangle.py: Python class that defines a rectangle. Builds on 2-rectangle.py with:
• Special method __str__ to print the rectangle with the # character (if either of width or height equals 0, the method returns an empty string.).


• 4. Eval is magic
• 4-rectangle.py: Python class that defines a rectangle. Builds on 3-rectangle.py with:
• Special method __repr__ to return a string representation of the rectangle.


• 5. Detect instance deletion
• 5-rectangle.py: Python class that defines a rectangle. Builds on 4-rectangle.py with:
• Special method __del__ that prints the message Bye rectangle... when a Rectangle is deleted.


• 6. How many instances
• 6-rectangle.py: Python class that defines a rectangle. Builds on 5-rectangle.py with:
• Public class attribute number_of_instances that is initialized to 0, incremented for each new instantiation, and decremened for each instance deletion.


• 7. Change representation
• 7-rectangle.py: Python class that defines a rectangle. Builds on 6-rectangle.py with:
• Public class attribute class_symbol that is initialized to # but can be any type - used as the symbol for string representation.


• 8. Compare rectangles
• 8-rectangle.py: Python class that defines a rectangle. Builds on 7-rectangle.py with:
• Static method def bigger_or_equal(rect_1, rect_2): that returns the rectangle with the greater area (returns rect_1 if both areas are equal).
• If either of rect_1 or rect_2 is not a Rectangle instance, a TypeError is raised with the message rect_1 must be an instance of Rectangle or rect_2 must be an instance of Rectangle.


• 9. A square is a rectangle
• 9-rectangle.py: Python class that defines a rectangle. Builds on 8-rectangle.py with:
• Class method def square(cls, size=0): that returns a new Rectangle instance with width == height == size.


• 10. N Queens



• 101-nqueens.py: Python program that solves the N queens puzzle.
• Usage: ./101-nqueens.py N.
• Determines all possible solutions for placing N non-attacking queens on an NxN chessboard.
• Exactly two arguments must be provided. Otherwise, the program prints Usage: nqueens N and exits with the status 1.
• If the provided N is not an integer, the program prints N must be a number and exits with the status 1.
• If the provided N is less than 4, the program prints N must be at least 4 and exits with the status 1.
• Solutions are printed one per line in the format [[r, c], [r, c], [r, c], [r, c]] where r and c represent the row and column, respectively, where a queen must be placed.