Quick Sort Algorithm:- Quick sort is the most famous sorting algorithm. It is the external sorting technique that is based on divide and conquer strategy. The Complexity of this algorithm is following:

Best Case:- O(n log n)
Average Case:- O(n log n)
Worst Case:- O(n^2)

#include<stdio.h>
#include<conio.h>

int split(int *,int,int);
void quick_sort(int *,int,int);

void main()
{
int arr[10],i,j,lw,up,mid;
clrscr();
printf("\nEnter 5 Unsorted Elements:=");
for(i=0;i<6;i++)
scanf("%d",&arr[i]);

lw=0;
up=6-1;
quick&#95;sort(arr,lw,up);
printf("\nSorted Array is:=\n");
for(i=0;i<6;i++)
printf("\n%d",arr[i]);
getch();
}

void quick_sort(int *a,int lw,int up)
{
int i;
    if(up>lw)
    {
        i=split(a,lw,up);
        quick_sort(a,lw,i-1);
        quick_sort(a,i+1,up);
    }
}

int split(int *a,int lw,int up)
{
int i=0,j=0,pivot,temp;
i=lw+1;
j=up;
pivot=a[lw];


while(j>=i)
{
    while(a[i]<pivot)
    i++;

    while(pivot<a[j])
    j--;

    if(j>i)
    {
       temp=a[i];
       a[i]=a[j];
       a[j]=temp;
    }

}
temp=a[lw];
a[lw]=a[j];
a[j]=temp;

return j;
}