First, something about the procedure that goes through this binary tree creating sorted array. We have a procedure get_value(node) that accepts as an argument the type of node and gets the node's data value and puts it in an array.  There are also two procedures named left(node) and right(node) that return the left or right child node of the parent node set as the argument (this means pointers to the left or right child-node). If this is clear, see the procedure for sorting.


BINARY_TREE_SORT(root)
if(root!=null) then
 BINARY_TREE_SORT(left(root))
 get_value(root)
 BINARY_TREE_SORT(right(root))
end_if



As it is shown this procedure is recursive and accepts one argument of type node. When we start this procedure it recursively calls itself until it reaches the further-most left child-node that has no left child of it's own. Then with a get_value procedure, it stores that node's data value in the array and again calls binary_tree_sort procedure for that node’s further-most right child.  This recursion goes on until all elements (all recursion ends) are visited. This algorithm is efficient for all kinds of binary trees and also known as "inorder tree visit".

Conclusion

I have presented two types of sorting methods: inserting and selection methods. In the next article we will go further with inner-sorting methods and I will try to present to you some linear-complex methods for sorting such as counting-sort, bucket-sort and distribution sort. Until then enjoy your sorting!