Question

Given n is a positive integer, do the following two programs display the same?

i = 0
while (i < n):
-> print (i)
-> i = i + 1

for i in range(0, n, 1):
-> print(i)
-> i = i - 1

Answer 1

Both programs actually output the same numbers from 0 to n-1. The unusual decrement in the for loop has no effect on the output due to Python's for loop behavior.

Step-by-step explanation:

The two programs in question do not output the same result. The first program, a while loop, will print numbers from 0 to n-1. As it uses a while loop, after printing each number, it increments the value of i by 1 until i is no longer less than n.

The second program, a for loop, intends to do the same by printing numbers from 0 to n-1. However, this code introduces a modification to i within the loop (i = i - 1), which is unusual because the for loop already controls the variable i. But due to the way for loops work in Python, the decrement inside the loop will have no effect on the iteration process because i is reassigned with the next value in the range on each iteration. Therefore, this code will also output numbers from 0 to n-1, just like the first program.

The intention of modifying the loop variable inside a for loop usually indicates a possible misunderstanding of how for loops work in Python, as it is not a common practice and it has no effect on the output.