### old

#### Program to compare shell and insertion sort methods.

```  ```

#include < iostream >
#include < iomanip >

using namespace std;
int insertcount=0;
int shellcount=0;
int shellSort(int arr[], int n)
{
// Start with a big gap, then reduce the gap
for (int gap = n/2; gap > 0; gap /= 2)
{
// Do a gapped insertion sort for this gap size.
// The first gap elements a[0..gap-1] are already in gapped order
// keep adding one more element until the entire array is
// gap sorted
for (int i = gap; i < n; i += 1)
{
// add a[i] to the elements that have been gap sorted
// save a[i] in temp and make a hole at position i
int temp = arr[i];

// shift earlier gap-sorted elements up until the correct
// location for a[i] is found
int j;
for (j = i; j >= gap && arr[j - gap] > temp; j -= gap)
arr[j] = arr[j - gap];

//  put temp (the original a[i]) in its correct location
arr[j] = temp;
}
shellcount++;
}
return 0;
}

void insertionSort(int arr[], int n)
{
int i, key, j;
for (i = 1; i < n; i++)
{
key = arr[i];
j = i - 1;

/* Move elements of arr[0..i-1], that are
greater than key, to one position ahead
of their current position */
while (j >= 0 && arr[j] > key)
{
arr[j + 1] = arr[j];
j = j - 1;
}
arr[j + 1] = key;
insertcount++;
}
}

int main()
{

int arr[] = { 12, 11, 13, 5, 6 };
int n = sizeof(arr) / sizeof(arr[0]);

cout<< "Shell sort "<< endl;
shellSort(arr, n);

cout<< endl<<"Time :" << shellcount<< endl;

cout<< endl<< endl;

cout<< "Insertion Sort"<< endl;
insertionSort(arr, n);

cout<< endl<<"Time :" << insertcount<< endl;
cout<< endl;

return 0;
}

```

```