Easy+ · digit building

Reverse a Number

12345 → 54321. Peel digits off the back and build them onto a new number — the most-asked interview warm-up there is.

Problem

Input: one integer n (0 ≤ n ≤ 10⁹).

Output: the digits of n in reverse order (as an integer — leading zeros disappear).

Sample:

Input	Output
`12345`	`54321`
`1000`	`1`

Program.cs — your solution

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Hint 1 — build, don't collect

No strings needed: rev = rev * 10 + n % 10; shifts what you have left and appends the peeled digit. Then n = n / 10;.

Hint 2 — why 1000 → 1

As an INTEGER, reversed "0001" is just 1 — the math drops leading zeros automatically. A string approach would need trimming.

Solution (try first!)

int n = int.Parse(Console.ReadLine());
int rev = 0;
while (n > 0) { rev = rev * 10 + n % 10; n = n / 10; }
Console.WriteLine(rev);

Note n = 0 never enters the while — rev stays 0, which prints correctly. Next: Palindrome Number.