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At school we are currently learning sorting algorithms in Java and I got for my homework the Heap Sort. I did my reading, I tried to find out as much as I could, but it seems I just can't grasp the concept.

I have written a bubble sort algorithm to sort a linked list. I am a Java beginner and trying to learn data structures. I am confused why my second element is not sorted properly.

I know there are natsort() and natcasesort() functions in php to sort array elements in natural order. I am trying to sort the following items.