Examples :

Input: arr[ ] = {1, 6, 9, 4, 3, 7, 8, 2}

Output : 9 1 8 2 7 3 6 4

Input : arr[ ] = {7, 1, 2, 3, 4, 5, 6}

Output : 7 1 6 2 5 3 4



#include <bits/stdc++.h>
using namespace std;

// Function to print alternate sorted values
void alternateSort(int arr[], int n)
{
    // Sorting the array
    sort(arr, arr + n);

    // Printing the last element of array
    // first and then first element and then
    // second last element and then second
    // element and so on.
    int i = 0, j = n - 1;
    while (i < j)
    {
        cout << arr[j--] << " ";
        cout << arr[i++] << " ";
    }

    // If the total element in array is odd
    // then print the last middle element.
    if (n % 2 != 0)
        cout << arr[i];
}

int main()
{
    int arr[] = {1, 12, 4, 6, 7, 10};
    int n = sizeof(arr) / sizeof(arr[0]);

   // OR
      // int arr[100], n;
    // cout << "Enter number of elements: ";
    // cin >> n;

    // for (int i = 0; i < n; i++)
    // {
    //     cout << "Enter element " << i + 1 << ": ";
    //     cin >> arr[i];
    // }

    alternateSort(arr, n);
    return 0;
}

Output:

12 1 10 4 7 6