Can anyone please explain me this

Question

Question:
You have a magic box that doubles the count of items you put, in every day.
The given program takes the initial count of the items and the number of days as input.

Task
Write a program to calculate and output items' count on the last day.

Solution:
items = int(input())
days = int(input())
#your code goes here
while days>0:
items*=2
days-=1
print(items)

Answer 1

Hello Kaushik

You take two user inputs: items and days (both are integer)

while days > 0: -> the loop will end when days gets 0

items *= 2 -> items = items * 2
items gets doubled.
days -= 1 -> days = days - 1
days gets reduced by 1.

Let's say I enter 3 items and 2 days.

days = 2
while condition returns true
items = 3 * 2 = 6
days = 2 - 1 = 1

days = 1
while condition returns true
items = 6 * 2 = 12
days = 1 - 1 = 0

days = 0
while condition returns false

print(items)
output: 12

Answer 2

items = int(input())
days = int(input())

The simplest way to get to the correct answer from there, would be to use exponentiation.

Total items, multiplied by 2 to the power of the number of days.

total = items*(2**days)