How do I fix my quickSort implementation? - c++

Question

So I've been trying to implement a quicksort but it seems not working
It keeps giving me a segmentation fault error 11
Can someone please help or give an advice on fixing this?
#include <iostream>
using namespace std;
void _quickSort(int arr[],int lo,int hi);
void quickSort(int arr[]) {
//lo = low(arr);
//hi = high(arr);
_quickSort(arr,0,9);
}
void _quickSort(int arr[], int lo, int hi) {
int p = lo;
//cout << lo << " " << hi << endl;
for (int i = lo; i < hi;i++) {
if (arr[i] < arr[p]) {
cout<<arr[i]<<" <-> "<<arr[p]<<endl;
swap(arr[i],arr[p]);
p = i;
}
}
_quickSort(arr,lo,p);
_quickSort(arr,p,hi);
}
int main() {
int a[] = {5,2,7,9,8,3,1,6,4};
quickSort(a);
for (int i = 0;i < 9;i++) {
cout << a[i] << " ";
}
}

Answer 1

#include <bits/stdc++.h>
using namespace std;
int _quickSort(int a[], int lb, int ub) {// lb-lower bound ub-upperbound
int start=lb;
int end=ub;
int pivot=a[lb];
while(start<end)
{
while(a[start]<=pivot)
start++;
while(a[end]>pivot)
end--;
if(start<end)
{
int temp=a[end];
a[end]=a[start];
a[start]=temp;
//cout<<a[start]<<" "<<a[end]<<" "<<pivot<<"\n";
}
}
int temp=a[end];
a[end]=a[lb];
a[lb]=temp;
return end;
}
void quickSort(int a[],int lb,int ub) {
if(lb<ub)
{
int pos=_quickSort(a,lb,ub);
quickSort(a,lb,pos-1);
quickSort(a,pos+1,ub);
}
}
int main() {
int a[9] = {5,2,7,9,8,3,1,6,4};
quickSort(a,0,8);
for (int i = 0;i <=8;i++)
{
cout << a[i] << " ";
}
}
This is an alternative way of implementing quicksort. Ive just returned the position of the pivot to another function and recursively calling the _quicksort from that.