I am attempting to make a collatz conjecture program, but I can't figure out how to check for even numbers this is my current code for it

    elif (original_collatz % 2) == 0:
        new_collatz = collatz/2

anyone have an idea how to check

i tried it with modulo but could figure out how it works, and my program just ignores this line, whole program: `

#collatz program
import time

collatz = 7
original_collatz = collatz
new_collatz = collatz

while True:
    if original_collatz % 2 == 1:
        new_collatz = (collatz * 3)   1

    elif (original_collatz % 2) == 0:
        new_collatz = collatz/2

    collatz = new_collatz

    print(collatz)

    if collatz == 1:
        print('woo hoo')
        original_collatz  = 1

    time.sleep(1)

CodePudding user response：

The problem is not that "your program ignore the lines", it's that you test the parity of original_collatz which doesn't change.

• You need to check the parity of collatz
• You need to use integer division (//) when dividing by two or collatz will become a float.
• You don't really need to use new_collatz as an intermediate, you could just overwrite collatz directly.

Here is a fixed sample:

# collatz program
import time

collatz = 7
original_collatz = collatz
new_collatz = collatz

while True:
    if collatz % 2 == 1:
        new_collatz = (collatz * 3)   1

    else:
        new_collatz = collatz // 2

    collatz = new_collatz

    print(collatz)

    if collatz == 1:
        print('woo hoo')
        original_collatz  = 1
        collatz = original_collatz

    time.sleep(1)

CodePudding user response：

Working example:

import time

collatz_init = 7
collatz = collatz_init

while True:
    if collatz % 2 == 1:
        collatz = (collatz * 3)   1
    else:
        collatz //= 2

    print(collatz)

    if collatz == 1:
        print('woo hoo')
        collatz_init  = 1
        collatz = collatz_init

    time.sleep(1)

CodePudding user response：

It seems that the prev. posts have pointed clearly your oringal problems.

Here is a simplified version to approach it, just for reference:

def collatz_sequence(x):
    ans = [x]
    if x < 1: return []
    while x > 1:
        if x & 1:          # odd num
            x = 3 * x   1
        else:              # even num
            x //= 2
        ans.append(x)
    return ans

print(collatz_sequence(100))
# collatz_sequence(100)
[100, 50, 25, 76, 38, 19, 58, 29, 88, 44, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1]