Quicksort; Segmentation Fault, but can't find where? - c++

Question

I made a quicksort algorithm as normal functions within main, then attempted to transfer it to a class (per what my instructor wanted). However, I am now getting a segmentation fault error, but I cannot figure out where it is occurring. Source code below; thanks.
main.cpp
#include "MergeSort.h"
#include "QuickSort.h"
#include <iostream>
using namespace std;
const int SIZE = 10;
int main() {
cout << "This is compiling.\n";
int testArray[SIZE] = {5,3,9,2,1,3,8,1,7,9};
for (int i = 0; i < SIZE; i++) {
cout << testArray[i];
}
QuickSort test(testArray, SIZE);
int * result = test.getArray();
cout << endl;
for (int i = 0; i < SIZE; i++) {
cout << result[i];
}
return 0;
}
QuickSort.cpp
#include "QuickSort.h"
//constructor
QuickSort::QuickSort(const int anArray[], int aSize) {
array_p = new int[aSize];
size = aSize;
for (int i = 0; i < size; i++)
array_p[i] = anArray[i];
quickSort(0, aSize - 1);
return;
}
//destructor
QuickSort::~QuickSort() {
delete [] array_p;
return;
}
//accessor function for array
int * QuickSort::getArray() {
return array_p;
}
//PRIV MEM FUNCTIONS
void QuickSort::quickSort(int start, int end)
{
if (start == end)
return;
int pivot;
pivot = partition(array_p, start, end);
//quickSort everything before where pivot is now
quickSort(start, pivot - 1);
//quickSort everything after where pivot is now
quickSort(pivot, end);
return;
}
int QuickSort::partition(int a[], int start, int end)
{
int first, last, pivot;
pivot = end;
first = start;
last = end - 1; //minus one is because pivot is at last
while (first < last) {
if (a[first] > a[pivot] && a[last] < a[pivot]) {
swap(a, first, last);
first++;
last--;
}
else {
if (a[first] <= a[pivot])
first++;
if (a[last] >= a[pivot])
last--;
}
}
if (a[pivot] > a[first]) {
swap(a, pivot, first + 1);
return first + 1;
}
else {
swap(a, pivot, first);
return first;
}
}
void QuickSort::swap(int a[], int indexOne, int indexTwo)
{
int temp = a[indexOne];
a[indexOne] = a[indexTwo];
a[indexTwo] = temp;
return;
}
I think it might be
quickSort(start, pivot - 1);
because once I comment it out, I do not get the error; however, I cannot figure out why.

Answer 1

Change quickSort(pivot, end);
to
quickSort(pivot+1, end);
and
if (start == end)
to if (start >= end).
Your code will run just fine now.