Cocktail Sort.cpp

// C++ implementation of Cocktail Sort
#include <bits/stdc++.h>
using namespace std;

// Sorts array a[0..n-1] using Cocktail sort
void CocktailSort(int a[], int n)
{
bool swapped = true;
int start = 0;
int end = n - 1;

while (swapped) {
// reset the swapped flag on entering
// the loop, because it might be true from
// a previous iteration.
swapped = false;

// loop from left to right same as
// the bubble sort
for (int i = start; i < end; ++i) {
if (a[i] > a[i + 1]) {
	swap(a[i], a[i + 1]);
	swapped = true;
}
}

// if nothing moved, then array is sorted.
if (!swapped)
break;

// otherwise, reset the swapped flag so that it
// can be used in the next stage
swapped = false;

// move the end point back by one, because
// item at the end is in its rightful spot
--end;

// from right to left, doing the
// same comparison as in the previous stage
for (int i = end - 1; i >= start; --i) {
if (a[i] > a[i + 1]) {
	swap(a[i], a[i + 1]);
	swapped = true;
}
}

// increase the starting point, because
// the last stage would have moved the next
// smallest number to its rightful spot.
++start;
}
}

/* Prints the array */
void printArray(int a[], int n)
{
for (int i = 0; i < n; i++)
printf("%d ", a[i]);
printf("\n");
}

// Driver code
int main()
{
int arr[] = { 5, 1, 4, 2, 8, 0, 2 };
int n = sizeof(arr) / sizeof(arr[0]);
CocktailSort(arr, n);
printf("Sorted array :\n");
printArray(arr, n);
return 0;
}