turner-townsend-backend-assessment/collatz/collatz.py

import readline


class CollatzCalculator:
    def calculate_steps(self, n: int) -> int:
        if n <= 1:
            return 0
        steps = 0
        while n != 1:
            if n % 2 == 0:
                n //= 2
                print(f"Step #{steps + 1}: even, divide by 2 -> {n}")
            else:
                n = 3 * n + 1
                print(f"Step #{steps + 1}: odd, multiply by 3 and add 1 -> {n}")
            steps += 1
        return steps + 1


def main():
    calculator = CollatzCalculator()
    while True:
        try:
            n = input("Please enter a whole number: ")
            print(
                f"Result: {calculator.calculate_steps(int(n))} steps needed to reach {n}"
            )
        except ValueError:
            print("ERROR: integer required")
        except (EOFError, KeyboardInterrupt):
            break


if __name__ == "__main__":
    main()