这段代码中找到素数分解有什么问题

Question

I tried to find the prime factorization using this code but the program enter an infinite loop. I tried to figure out what makes the program enter this infinite loop but unfortunately I couldn't. The code is:

N = int(input())
B = N
L = []
while B != 1:
    for i in range(2,N):
        if N % i ==0:
            L.append(i)
            B = N // i
            break
    else:
        L.append(N)
        B = 1
L.pop()
print(L)

Answer 1

The problem is with break statement, every time when for loop begins and the condition if N % i ==0 is reached forces to start a new for loop and this creates an infinity loop. So what you have to do is removing break

N = int(input())
B = N
L = []
while B != 1:
    for i in range(2,N):
        if N % i ==0:
            L.append(i)
            B = N // i
    else:
        L.append(N)
        B = 1
L.pop()
print(L)

Prints out:

>>10
>>[2, 5]

EDIT

That's the problem with infinity loop, but won't give you the right answer in some cases eg 20 because its logic is wrong. I modified a little bit the code and this is what I have.

N = int(input())
B = N
L = []
while B != 1:
    for i in range(2,N):
        if N % i ==0:
            L.append(i)
            N = N // i
            break
    else:
        L.append(N)
        B = 1
print(L)

Answer 2

while B != 1: is giving you an infinite loop. You can use a debugger and see that when, for example, N = 9, B never goes to 1 and the script keeps appending 3 to L forever.

Answer 3

You never increment i. The break statement takes you to "while b!= 1". So it appends 2 (or the first factor of N) to L infinitely.