How to show the output?

#1

Does the output needs to be shown in this format
2 => 1 <= END
3 => 2 <= END
END => 3 <= END
of just a simple preorder view?
if not simple preorder, explain how to cout the output?

#2

refer my code https://ide.codingblocks.com/s/629860
u will understand the format of printing o/p

#3

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#4

What is the error in my code? https://ide.codingblocks.com/s/631950