How to modify this tree iteration code to iterate in an ordered way?

This piece of code iterates over a tree of TreeNode objects where every object may have childs (from an Answer to this question: iPhone-friendly alternative to recursion over huge tree structures?).

-(void)iterateOverTree:(TreeNode *)node
{
    NSMutableArray * elements = [NSMutabl开发者_开发技巧eArray array];
    [elements addObject:node];

    while([elements count])
    {
        TreeNode * current = [elements objectAtIndex:0];
        [self doStuffWithNode:current];
        for(TreeNode * child in current.children)
        {
            [elements addObject:child];
        }

        [elements removeObjectAtIndex:0];
    }
}

The problem is that this code does not walk through the tree in an ordered way.

i.E. I have this: A owns B, J B owns C owns D owns E J owns K owns L owns M (note: "owns" means "has child". A has two childs while the rest has one or none)

This is how the tree is traversed: A, B, J, C, K, D, L, ...

But I want: A, B, C, D, E, J, K, L, M, ...

in an ordered way, just like it happens with recursion.

How could I change that in such a way that it traverses the tree ordered, like in the example above?

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You want depth first search. Currently you're performing breadth first search.

I don't know Objective-C, but it looks like you're using NSMutableArray as a queue. Use it as a stack for non-recursive depth first search.