quick sort

#include<iostream>
#include <bits/stdc++.h>
using namespace std;

int partition(int A[], int lb, int ub) {
    int pivot = A[lb];
    int start = lb;
    int end = ub;

    while (start < end) {
        while (A[start] <= pivot) { 
            start++;
        }
        while (A[end] > pivot) { 
            end--;
        }
        if (start < end) {
            swap(A[start], A[end]); 
        }
    }
    swap(A[lb], A[end]); 
    return end; 
}

void quicksort(int A[], int lb, int ub) {
    if (lb < ub) {
        int loc = partition(A, lb, ub);
        quicksort(A, lb, loc - 1);
        quicksort(A, loc + 1, ub);
    }
}

int main() {
    int n;
    cout << "Enter the array size: ";
    cin >> n;
    int a[n];
    cout << "Enter array values: ";
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    quicksort(a, 0, n - 1);
    cout << "Sorted array: ";
    for (int z = 0; z < n; z++) {
        cout << a[z] << " ";
    }
    cout << endl;
    return 0;
}