Question

I have a class named move
it has a field named val of type int
And I have a list of moves named mlist

I wrote this

mlist.Sort((b, a) =>
    {
       if (a.val > b.val)
           return 1;
       else if (a.val == b.val)
           return 0;
       else
           return -1;
    }
    );

at first my list have two objects that both has .val = 0
when I sort the list the place of these two object is changed. But I don’t want to this to happen. What can I do?

Answer 1

Sort performs a quicksort which is an unstable sort.

If you want a stable sort you could use the OrderBy method which is available through LinQ

Using OrderBy in your example would be assuming that mList is a List<>

mList = mList.OrderBy(a => a.val).ToList();

Should you desire the reverse ordering, the method is called OrderByDescending