Implement Shell sort algorithm in C++

Code

    // shell sort

    #include <iostream>

    using namespace std;

    int main()
    {
        int n, i, j, temp, gap;
        int arr[50];
        cout << "Enter the size of array: ";
        cin >> n;
        cout << "Enter the elements of array: " << endl;
        for (i = 0; i < n; i++)
        {
            cin >> arr[i];
        }
        for (gap = n / 2; gap >= 1; gap = gap / 2)
        {
            for (i = gap; i < n; i++)
            {
                temp = arr[i];
                j = i - gap;
                while (temp < arr[j] && j >= 0)
                {
                    arr[j + gap] = arr[j];
                    j = j - gap;
                }
                arr[j + gap] = temp;
            }
        }
        cout << "Sorted array: ";
        for (i = 0; i < n; i++)
        {
            cout << arr[i] << " ";
        }

        cout << endl;
        return 0;
    }

Output

Enter the size of array: 6
Enter the elements of array: 
23
45
23
45
47
42
Sorted array: 23 23 42 45 45 47