Iterative MergeSort function

[DreamTime]

I am trying to write an iterative MergeSort function. I have already written it recursively. I have to use this "Merge" function for both the recursive and iterative MergeSort function

void Merge(vector<int> &a, int front, int mid, int end)
{
	int *temp;
	int size = end - front + 1;

	temp = new int[size];

	int front1 = front;
	int end1 = mid;
	int front2 = mid + 1;
	int end2 = end;
	int index = 0;

	while ((front1 <= end1) && (front2 <= end2))
	{
		if (a[front1] < a[front2])
		{
			temp[index] = a[front1];
			front1++;
		}
		else
		{
			temp[index] = a[front2];
			front2++;
		}
		index++;
	}

	while (front1 <= end1)
	{
		temp[index] = a[front1];
		front1++;
		index++;
	}

	while (front2 <= end2)
	{
		temp[index] = a[front2];
		front2++;
		index++;
	}

	for (index = 0; index < size; index++)
	{
		a[front] = temp[index];
		front++;
	}

	delete[] temp;
}

Right now, my recursive MergeSort works. But I am unable to get the Iterative MergeSort to work. With this code, I am only able to partially sort the array.

void IterativeMergeSort(vector<int> &a, int front, int end)
{
	for(int i = 1; i <= end; i *= 2)
	{
		for(int j = i; j <= end; j += (2 * i))
		{
			Merge(a, j - i, j, min((j + i), end));
		}
	}
}

When I try to sort an array with the following values
[1, 7, 4, 0, 9, 8, 2, 5, 6, 3]

My iterative sort method only sorts part of it
[0, 1, 2, 3, 4, 7, 8, 5, 9, 6]

I tried playing around with the <= and <, and I usually end up getting a vector subscript out of range error. I don't really understand where my code is wrong. Can anyone offer any advice on what I am doing incorrectly?

[coder777]

Please provide the code to reproduce the problem.