# C++ Program for Comb Sort?

The basic idea of comb sort and the bubble sort is same. In other words, comb sort is an improvement on the bubble sort. In the bubble sorting technique, the items are compared with the next item in each phase. But for the comb sort, the items are sorted in a specific gap. After completing each phase, the gap is decreased. The decreasing factor or the shrink factor for this sort is 1.3. It means that after completing each phase the gap is divided by 1.3. Time Complexity is O(n log n) for best case. O(n2/2nP) (p is number of increment) for average case and O(n2) for worst case.

## Algorithm

#### CombSort(array, size)

Input − An array of data, and the total number in the array

Output − The sorted Array

Begin
gap := size
flag := true
while the gap ≠ 1 OR flag = true do
gap = floor(gap/1.3) //the the floor value after division
if gap < 1 then
gap := 1
flag = false
for i := 0 to size – gap -1 do
if array[i] > array[i+gap] then
swap array[i] with array[i+gap]
flag = true;
done
done
End

## Example

include<iostream>
#include<algorithm>
using namespace std;
void display(int *array, int size){
for(int i = 0; i<size; i++)
cout << array[i] << " ";
cout << endl;
}
void combSort(int *array, int size){
int gap = size; //initialize gap size with size of array
bool flag = true;
while(gap != 1 || flag == true){
gap = (gap*10)/13; //minimize gap by shrink factor
if(gap<1)
gap = 1;
flag = false;
for(int i = 0; i<size-gap; i++){ //compare elements with gap
if(array[i] > array[i+gap]){
swap(array[i], array[i+gap]);
flag = true;
}
}
}
}
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 elements:" << endl;
for(int i = 0; i<n; i++){
cin >> arr[i];
}
cout << "Array before Sorting: ";
display(arr, n);
combSort(arr, n);
cout << "Array after Sorting: ";
display(arr, n);
}

## Output

Enter the number of elements: 10
Enter elements:
108 96 23 74 12 56 85 42 13 47
Array before Sorting: 108 96 23 74 12 56 85 42 13 47
Array after Sorting: 12 13 23 42 47 56 74 85 96 108

Updated on: 30-Jul-2019

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