Quick Sort

quickSort.cpp

#include <iostream>
using namespace std;

int partition(int *, int, int);
void printArray(int *, int);

void quickSort(int *arr, int start, int end) {
    if(start < end) {
        int q = partition(arr, start, end);
        quickSort(arr, start, q);
        quickSort(arr, q+1, end);
    }
}

int partition(int *arr, int start, int end) {
    int i = start;
    int checker = arr[end-1];
    for(register int  j = start; j < end - 1; j++) {
        if(arr[j] < checker) {
            swap(arr[j], arr[i]);
            i++;
        }
    }
    swap(arr[i], arr[end-1]);
    return i;
}

void printArray(int *arr, int size) {
    for(register int i=0; i<size; i++)
        cout<<arr[i]<<" ";
    cout<<endl;
}

int main() {
    int arr[] = {5, 6, 0, 13, 3, 2, 8, 7, 4};
    int n = 9;
    quickSort(arr, 0, n);
    printArray(arr, n);

    return 0;
}