Quick Sort

QuickSort.cpp

void Swap(int array[], int a, int b)
{
	int tmp = array[a];
	array[a] = array[b];
	array[b] = tmp;
}

void PrintArray(int array[], int length, int lower, int upper)
{
	for (int i = 0; i < length; ++i)
	{
		if (i == lower || i == upper)
			cout << '[' << array[i] << "] ";
		else
			cout << array[i] << ' ';
	}
	cout << endl;
}

void PrintRange(int array[], int length, int begin, int end)
{
	for (int i = 0; i < length; ++i)
	{
		if (i == begin)
			cout << '<';

		cout << array[i];
		
		if (i == end)
			cout << '>';

		cout << ' ';
	}
	cout << endl;
}

//Partition the array within range [lower, upper] into 2 parts
int Partition(int array[], int lower, int upper)
{
	PrintRange(array, 9, lower, upper);

	//Is lower index represent the base value
	bool base_lower = true;

	while (upper > lower)
	{
		PrintArray(array, 9, lower, upper);

		if (array[lower] > array[upper])
		{
			Swap(array, lower, upper);
			//After swap
			PrintArray(array, 9, lower, upper);
			base_lower = !base_lower;
		}
		
		//If base value is on the lower side, check the next upper value
		if (base_lower)
		{
			upper--;
		}
		//If base value is on the upper side, check the next lower value
		else
		{
			lower++;
		}
	}

	return lower;
}

void QuickSort(int array[], int lower, int upper)
{
	if (lower < upper)
	{
		int p = Partition(array, lower, upper);
		QuickSort(array, lower, p - 1); //Sort lower part
		QuickSort(array, p + 1, upper); //Sort upper part
	}
}