Shell Sort Algorithm in C++

Shell sort is a sorting algorithm that uses a gap between elements to compare the values. The gap between elements shrinks until is 0 and the array is sorted. This technique is based on Insertion Sort, but in shell sort we avoid shifting large interval of elements by using specific interval.

// Shell Sort

#include <iostream>
using namespace std;

int shellSort(int arrayOfNumbers[], int numberOfElements)
{
    // Set the first gap as half of the array, then divide it by 2
    for (int gap = numberOfElements/2; gap > 0; gap /= 2)
    {
        // Insertion Sort for this gap
        for (int i = gap; i < numberOfElements; i += 1)
        {
            int temp = arrayOfNumbers[i];

            // Shift elements
            int j;
            for (j = i; j >= gap && arrayOfNumbers[j - gap] > temp; j -= gap)
            {
                arrayOfNumbers[j] = arrayOfNumbers[j - gap];
            }
            arrayOfNumbers[j] = temp;
        }
    }
    return 0;
}
void printElementsOfArray(int arrayOfNumbers[], int numberOfElements)
{
  for (int i = 0; i < numberOfElements; ++i)
  {
    cout << arrayOfNumbers[i] << " ";
  }
  cout << endl;
}

int main(void)
{
  int arrayOfNumbers[] = {4, 7, 9, 3, 21, 18, 23, 15, 8, 17};
  int numberOfElements = sizeof(arrayOfNumbers) / sizeof(arrayOfNumbers[0]);

  shellSort(arrayOfNumbers, numberOfElements);
  cout<<"The sorted array is: \n";
  printElementsOfArray(arrayOfNumbers, numberOfElements);
}