Answer: Python Puzzler #3834

The answer is D. The program prints:

45

This answer was checked by running the program for real.

Why?

The loop remembers the biggest number it has seen so far, and replaces it whenever it finds a bigger one. This is how computers find the maximum.

Trace table

A trace table follows the program step by step. Here’s this one:

n	n > biggest?	biggest
42	yes	42
35	no	42
45	yes	45
30	no	45
43	no	45

The code again

numbers = [42, 35, 45, 30, 43]
biggest = 0
for n in numbers:
    if n > biggest:
        biggest = n
print(biggest)