Day 49 : Python Program to Test Collatz Conjecture for a Given Number

def collatz_conjecture(n):

    if n <= 0:

        print("Please enter a positive integer.")

        return

     print(f"Starting number: {n}")

    while n != 1:

        if n % 2 == 0:

            n = n // 2

        else:

            n = 3 * n + 1

        print(n, end=" ")

    print("\nReached 1!")

try:

    number = int(input("Enter a positive integer to test the Collatz conjecture: "))

    collatz_conjecture(number)

except ValueError:

    print("Invalid input! Please enter a valid integer.")

#source code --> clcoding.com 

Code Explanation:

1. Function Definition

def collatz_conjecture(n):

This function implements the Collatz sequence starting from the number n.

2. Input Validation

if n <= 0:

    print("Please enter a positive integer.")

    return

The Collatz Conjecture only applies to positive integers.

If the input n is not a positive number (e.g., 0 or a negative number), the function prints an error message and exits using return.

3. Start the Sequence

print(f"Starting number: {n}")

Prints the starting number to indicate the beginning of the Collatz sequence.

4. Collatz Algorithm

while n != 1:

    if n % 2 == 0:

        n = n // 2

    else:

        n = 3 * n + 1

    print(n, end=" ")

while n != 1:

The loop runs until the number n becomes 1.

if n % 2 == 0:

Checks if n is even. If true, divide n by 2 (n = n // 2).

else:

If n is odd, apply the formula 3 * n + 1.

print(n, end=" "):

Prints the value of n after each step.

end=" " ensures all numbers are printed on the same line, separated by spaces.

5. Reached the End

print("\nReached 1!")

Once the loop ends (i.e., n == 1), this message is printed.

Error Handling

try:

    number = int(input("Enter a positive integer to test the Collatz conjecture: "))

    collatz_conjecture(number)

except ValueError:

    print("Invalid input! Please enter a valid integer.")

try-except Block:

Handles errors if the user enters invalid input (e.g., letters or symbols instead of numbers).

int(input()):

Prompts the user to enter a number and converts it to an integer.

ValueError:

If the user enters non-numeric input, Python raises a ValueError.

The program catches this error and prints an error message.