Quick sort

code:--

//NOT COMPLETE
#include<iostream>
#include<vector>
using namespace std;
int part(vector<int> & v,int start,int end)
{
int pivot=end;
int part_index=start;
for(int i=start;i<end;++i)
{
if(v[i]<=v[pivot])
{
swap(v[i],v[part_index]);
++part_index;
}
}
swap(v[part_index],v[pivot]);
return part_index;
}
void quicksort(vector<int> &v,int start,int end)
{
if(start>=end)
return;
int index=part(v,start,end);
quicksort(v,start,index-1);
quicksort(v,index+1,end);
}
int main()
{
int t;
cin>>t;
while(t--)
{
int n;
cin>>n;
vector<int> arr(n);
for(int i=0;i<n;++i)
cin>>arr[i];
quicksort(arr,0,n-1);
for(vector<int> ::iterator itr=arr.begin();itr!=arr.end();++itr)
{
cout<<*itr<<" ";
}
}
return 0;
}