Most partitioning implementations depend on where the pivot is, but not this one.

partition.cpp

#include "bits/stdc++.h"
using namespace std;

int partition(int a[], int low, int high) {
    /* try with different values of p in range [low, high] */
    int p = (low + high) / 2;

    int i = low;
    int j = high;
    while (1) {
        while (a[i] <= a[p] && i != p)
            i++;
        while (a[j] > a[p])
            j--;
        if (i < j) {
            if (i == p)
                p = j;
            else if (j == p)
                p = i;
            swap(a[i], a[j]);
        } else
            return p;
    }
}

int main() {
    int a[] = {1, 234, 43, 24, 2, 46, 426, 456, 97, 64, 2, 93, 24};
    int n = sizeof(a) / 4;
    
    partition(a, 0, n - 1);
    
    for (int i = 0; i <= n - 1; i++)
        cout << a[i] << " ";
    cout << "\n";
    
    return 0;
}