Quick sort Simplest Programming Solution in c program

Quick sort Simplest Programming Solution.


#include<stdio.h>
#include<math.h>
void quicksort(int *ar,int start,int end);      
int  divide(int *ar,int start,int end,int pivot);

void main(){
        int size;
        int itr;
        printf("Enter size of array\n");
        scanf("%d",&size);
        int a[size];
        for(itr=0;itr<size;itr++){
        printf("enter %d element\n",itr+1);
    scanf("%d",&a[itr]);
        }
        quicksort(a,0,size-1);
    for(itr=0;itr<size;itr++)
        printf(" element %d \n",a[itr]);

}

void quicksort(int *ar,int start,int end){
        if(start < end) {
        int pivot = start;
            pivot = rand() % (end - start) + start ;
            pivot = divide(ar,start,end,pivot);
            quicksort(ar,start,pivot-1);
            quicksort (ar,pivot+1,end);
    }
}      
int  divide(int *ar,int start,int end,int pivot){
        int itr,temp,next,next1;
        temp =ar[pivot];
        ar[pivot]=ar[start]; 
        ar[start]=temp;
        pivot =start;
        next =start+1;
        while(next<=end){
                if(ar[next]>ar[pivot]){
                        temp = ar[next];
            next1 = next;
                        while(next1!=pivot+1){
                               ar[next1]=ar[next1-1];
                                next1--;
                        }
                        ar[next1]=ar[pivot];
                        ar[pivot]=temp;
                        pivot++;
                }
            next++;
    }
return pivot;   
}