CODEWITHSUNDEEP
pythonmath
Misha
Misha

Reputation: 57

Collatz Conjecture program randomly stops being accurate at high digits

So while Wikipedia surfing, I stumbled onto the Collatz Conjecture So I decided to write a simple python program, 

while True:
x = int(input("Enter a number: "))
n=0

 while True:
     if  (x % 2) == 0:
         x = x/2
         n += 1
         print(x)
     else:
         x = 3*x +1
         n+=1
         print(x)
     if x == 1:
        break
print("N = %d" %(n))

At first I played around with random numbers, and then I decided to test some of the larger numbers that the Wikipedia article represents. The program worked perfectly up until 75,128,138,247 on Wikipedia's " Examples" Section,previously it matched the number of steps exactly, and then it just randomly says "512" for N (the number of steps. I just don't understand why. Can anyone Help?

Upvotes: 1

Views: 79

Answers (1)

MBo
MBo

Reputation: 80232

Float division might cause issues (note output as floats), so work in integers:

change

x = x/2

to integer division (your print correponds to Python 3, so it is available)

x = x // 2

Upvotes: 2

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