Programming, problem solving, and algorithms

CPSC 203, 2025 W1

September 18, 2025

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Back to handcraft

Where are we?

The 8x8 grid illustrates dishcloth. Each block has 5 rows of 5 stitches. How would you represent a handcraft using Python types?

Program design

A handcraft is a collection of __________. Every __________ has a __________, and a collection of __________. Every __________ is a collection of __________. Every __________ is either “knit” or “purl,” and is drawn as a __________.

Missing words: blocks, blocks, position, rows, stitches, rectangles

Classes in Python

Mechanism for creating user-defined types.

Used to identify attributes with an object. Associates functionality with the relevant objects.

Example:

@dataclass
class color:
  """
  color: simply gathers color components
  """
  red: int = 120
  green: int = 120
  blue: int = 120

Data classes allow us to create substructures to organize data in a way useful to us. Attributes are data and the functionality are member functions. Attributes can be defined with default values.

Using a Data Class

@dataclass
class color:
  """
  color: simply gathers color components
  """
  red: int = 120
  green: int = 120
  blue: int = 120

Declaring an object of type color():

Accessing the data of an object of type color():

Design Strategies

1. Decompose a problem into classes

2. List the data associated with each class

3. Write the “driver” code that illustrates the functionality you expect from each class.

4. Implement the functions you expect.

5. Run the driver code to test your functionality.

Which classes?

Handcraft:

Block:

Row:

Stitch:

Image:

The 8x8 grid illustrates dishcloth. Each block has 5 rows of 5 stitches. How would you represent a handcraft using Python types?

Let’s Write

https://us.prairielearn.com/pl/course_instance/193300/assessment/2588207