Add armstrong number checker by amandapanda00.

[amandapanda00]

main.py, test_main.py, numbers.txt, readme.md

[ghostdeveloper404]

Hi @amandapanda00 — thanks for the contribution! I reviewed week1_projects/amandapanda00/armstrong_number_checker/main.py. Please make the following changes to improve correctness, robustness, and maintainability:

1. Fix module docstring

• Change "sum of the cubes of its digits" to the general definition: an Armstrong number equals the sum of each digit raised to the power of the number of digits.

2. Handle negative input

• Reject negative integers (return False) or explicitly document that only non-negative integers are supported. Current code will crash on negative input because of the '-' character in str(number).

Suggested change:
def is_armstrong(number: int) -> bool:
if number < 0:
return False
digits = [int(d) for d in str(number)]
n = len(digits)
return sum(d ** n for d in digits) == number

3. Improve file handling

• Open files with explicit encoding (encoding="utf-8").
• Prefer pathlib.Path for clearer checks (exists/is_file).
• Keep existing FileNotFoundError/PermissionError handling but check path first to provide clearer messages.

4. Make functions more testable

• Keep is_armstrong pure (it already is).
• Have process_result return the formatted string instead of printing directly; main() can print it. This makes unit testing easier.

5. Input robustness and UX

• Catch KeyboardInterrupt and EOFError in main to exit gracefully.
• Validate filename input (strip and ignore empty input).
• Consider rejecting lines that contain non-digit characters (or handle leading '+') and report which lines are invalid.

6. Clean up comments and add type hints

• Remove noisy inline comments like "# og had ** 3".
• Add type hints for public functions (e.g., process_file(filename: str) -> None).
• Improve docstrings (PEP 257 style).

7. Tests and CI

• Add unit tests (pytest or unittest) covering:
  • Typical Armstrong numbers: 153, 370, 9474
  • Non-Armstrong numbers
  • 0
  • Negative values
  • File input with invalid lines
• Consider adding a simple GitHub Actions workflow to run tests.

8. Optional improvements (nice-to-have)

• Use argparse for CLI options (single number vs filename).
• Limit maximum allowed digits/value to avoid CPU/memory DoS from huge inputs and report if input is too large.