[Type B] Python Revision Tour-1 – Chapter 1

5. Is the loop in the code below infinite? How do you know (for sure) before you run it?

m = 3
n = 5
while n < 10 :
    m = n - 1
    n = 2 * n - m
    print(n, m)

The loop is not infinite. We can know this before running the code by analyzing the operations within the loop:

• m = n - 1: m will be 4 initially.
• n = 2 * n - m: n will be 2 * 5 - 4, which is 6.
• Output: 6 4
• Then, m becomes 5, and n becomes 2 * 6 - 5, which is 7.
• Output: 7 5
• Then, m becomes 6, and n becomes 2 * 7 - 6, which is 8.
• Output: 8 6
• Since 8 >= 10, the loop stops. Therefore, it’s not infinite.