Cyclically rotate an array by one.cpp

/*
Cyclically rotate an array by one
=================================

Given an array, rotate the array by one position in clock-wise direction.

Example 1:
Input:
N = 5
A[] = {1, 2, 3, 4, 5}
Output:
5 1 2 3 4

Example 2:
Input:
N = 8
A[] = {9, 8, 7, 6, 4, 2, 1, 3}
Output:
3 9 8 7 6 4 2 1

Your Task:  
You don't need to read input or print anything. Your task is to complete the function rotate() which takes the array A[] and its size N as inputs and modify the array.

Expected Time Complexity: O(N)
Expected Auxiliary Space: O(1)

Constraints:
1<=N<=105
0<=a[i]<=105
*/

//User function Template for C++

void rotate(int arr[], int n)
{
  int elem = arr[n - 1];
  for (auto i = n; i >= 1; --i)
  {
    arr[i] = arr[i - 1];
  }
  arr[0] = elem;
}