Read a whole number and print it with its digits in reverse order, as a number. Leading zeros disappear: 1200 becomes 21.
What to build
A loop that builds one number from another.
Requirements
- Read the number.
- Print its digits in reverse order, as a number.
Input
One whole number from 0 to 1000000000.
Output
The reversed number.
Constraints
The number is from 0 to 1000000000.
Example
Input:
1234
Output:
4321
Why it works
Multiplying the result by 10 makes room for the next digit, and leading zeros disappear because the result is a number, not text.
Examples
Example 1 · Input
1234
Expected output
4321
Example 2 · Input
1200
Expected output
21
Prompts inside input() are ignored when checking, so input("n: ") is fine.
Hints
Hint 1
Each round: reversed_n = reversed_n * 10 + n % 10.
Solution
Show one correct solution (try it yourself first)
n = int(input())
reversed_n = 0
while n > 0:
reversed_n = reversed_n * 10 + n % 10
n //= 10
print(reversed_n)