/***************************************************************
* Name: Rafael Orta
* Course: Computer Science & Programming
* Class: PDS-04225
* Date: 04/10/22
* File Name: InsertionSort.cpp
*****************************************************************
* Purpose: Demonstrate the implementation of the Shell sort algorithm
* using C++
*****************************************************************/
#include <iostream>
using namespace std;
void swapping(int&, int&);
void display(int*, int);
void shellSort(int*, int);
int main() {
int n;
cout << "Enter the number of elements: ";
cin >> n;
int arr[n]; //create an array with given number of elements
cout << "Enter the " << n << " elements separated by space:" << endl;
for(int i = 0; i<n; i++) {
cin >> arr[i];
}
cout << "Array before Sorting: ";
display(arr, n);
shellSort(arr, n);
cout << "Array after Sorting: ";
display(arr, n);
}
void swapping(int &a, int &b) { //swap the content of a and b
int temp;
temp = a;
a = b;
b = temp;
}
void display(int *array, int size) {
for(int i = 0; i<size; i++)
cout << array[i] << " ";
cout << endl;
}
void shellSort(int *arr, int n) {
int gap, j, k;
for(gap = n/2; gap > 0; gap = gap / 2) { //initially gap = n/2,
//decreasing by gap /2
for(j = gap; j<n; j++) {
for(k = j-gap; k>=0; k -= gap) {
if(arr[k+gap] >= arr[k])
break;
else
swapping(arr[k+gap], arr[k]);
}
}
}
}
