8.1

#include <iostream>
#include <vector>
using namespace std;
void Qsort(vector<int> &a, int first, int last)
{
    int l, r, vr, x;
    if (first < last)
    {
        x = a[(last + first) / 2];
        l = first; r = last;
        while (l <= r)
        {
            while (a[l] < x)l++;
            while (a[r] > x)r--;
            if (l <= r)
            {
                vr = a[l];
                a[l] = a[r];
                a[r] = vr;
                l++; r--;
            }
        }
        Qsort(a, first, r);
        Qsort(a, l, last);
    }
}
int main()
{
vector<int> array = { 6, 9,66,785,632,569,56,654,2,0, 31,23,33};
Qsort(array, 0, array.size() - 1);
for(int i=0;i<array.size();i++)
cout<<array[i]<< " ";
}