Question

I have been working on this for the past 5 hours. For some reason I am not getting the result I am looking for. The method is supposed to sort an ArrayList of items by quantity using bubble sort. Not sure if I am making a mistake but it seems to only sort the first few items and just lists the rest as they are and not in order.
Here is the code:

public static void bubblesrt(ArrayList<Drinks> list)
{
    Drink temp;
    if (list.size()>1) // check if the number of orders is larger than 1
    {
        for (int x=0; x<list.size(); x++) // bubble sort outer loop
        {
            for (int i=0; i < list.size()-i; i++) {
                if (list.get(i).compareTo(list.get(i+1)) > 0)
                {
                    temp = list.get(i);
                    list.set(i,list.get(i+1) );
                    list.set(i+1, temp);
                }
            }
        }
    }

}

and this is the compareTo() method which is located in a Drinks class

public int compareTo(Drinks z) 
{
    int res=0;
    if (quantity < z.quantity) {res = -1;}
    if (quantity > z.quantity) {res = 1;}
    return res;
}

How do I make this work as intended?

Answer 1

Try changing

list.add(i,list.get(i+1) );

to

list.set(i,list.get(i+1) );

and

for (int i=0; i < list.size()-i; i++)

to

for (int i=0; i < list.size() - x - 1; i++)