# C++ Program for Comb Sort

• Last Updated : 28 Jul, 2022

Comb Sort is mainly an improvement over Bubble Sort. Bubble sort always compares adjacent values. So all inversions are removed one by one. Comb Sort improves on Bubble Sort by using gap of size more than 1. The gap starts with a large value and shrinks by a factor of 1.3 in every iteration until it reaches the value 1. Thus Comb Sort removes more than one inversion counts with one swap and performs better than Bubble Sort.
The shrink factor has been empirically found to be 1.3 (by testing Combsort on over 200, 000 random lists) [Source: Wiki]
Although, it works better than Bubble Sort on average, worst case remains O(n2).

## CPP

 `// C++ implementation of Comb Sort` `#include ` `using` `namespace` `std;`   `// To find gap between elements` `int` `getNextGap(``int` `gap)` `{` `    ``// Shrink gap by Shrink factor` `    ``gap = (gap * 10) / 13;`   `    ``if` `(gap < 1)` `        ``return` `1;` `    ``return` `gap;` `}`   `// Function to sort a[0..n-1] using Comb Sort` `void` `combSort(``int` `a[], ``int` `n)` `{` `    ``// Initialize gap` `    ``int` `gap = n;`   `    ``// Initialize swapped as true to make sure that` `    ``// loop runs` `    ``bool` `swapped = ``true``;`   `    ``// Keep running while gap is more than 1 and last` `    ``// iteration caused a swap` `    ``while` `(gap != 1 || swapped == ``true``) {` `        ``// Find next gap` `        ``gap = getNextGap(gap);`   `        ``// Initialize swapped as false so that we can` `        ``// check if swap happened or not` `        ``swapped = ``false``;`   `        ``// Compare all elements with current gap` `        ``for` `(``int` `i = 0; i < n - gap; i++) {` `            ``if` `(a[i] > a[i + gap]) {` `                ``swap(a[i], a[i + gap]);` `                ``swapped = ``true``;` `            ``}` `        ``}` `    ``}` `}`   `// Driver program` `int` `main()` `{` `    ``int` `a[] = { 8, 4, 1, 56, 3, -44, 23, -6, 28, 0 };` `    ``int` `n = ``sizeof``(a) / ``sizeof``(a);`   `    ``combSort(a, n);`   `    ``printf``(``"Sorted array: \n"``);` `    ``for` `(``int` `i = 0; i < n; i++)` `        ``printf``(``"%d "``, a[i]);`   `    ``return` `0;` `}`

Output:

```Sorted array:
-44 -6 0 1 3 4 8 23 28 56```

Time Complexity: The worst-case complexity of this algorithm is O(n2).
Auxiliary Space: O(1).

Please refer complete article on Comb Sort for more details!

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