Shell_Sort

#include  <iostream> 
using namespace std; 
  
// function to sort array using shellSort 
int shellSort(int arr[], int n) { 
    // Start with a considerable gap, then reduce the gap 
    for (int interval = n/2; interval > 0; interval /= 2) { 
        // Do a gapped insertion sort for this gap size. 
       
        for (int i = interval; i < n; i += 1) { 

            int temp = arr[i]; 
            
            int j;             
            for (j = i; j >= interval && arr[j - interval] > temp; j -= interval) 
                arr[j] = arr[j - interval]; 
              
            //  put temp (the original a[i]) in its correct location 
            arr[j] = temp; 
        } 
    } 
    return 0; 
} 
  
void printArray(int arr[], int n) { 
    for (int i=0; i<n; i++) 
        cout << arr[i] << " "; 
} 
  
int main() { 
    int n;
    int arr[1000];
    for(int i=0;i<n;i++){
    cin>>arr[i];
    }
  
    cout << "Array before"<<endl; 
    printArray(arr, n); 
  
    shellSort(arr, n); 
  
    cout << "Array after :"<<endl; 
    printArray(arr, n); 
  
    return 0; 
}