Complete the function in your editor below, which has parameter: a pointer to the root of a binary tree. It must print the values in the tree's postorder traversal as a single line of space-separated values.
Our hidden tester code passes the root node of a binary tree to your function.
Nodes in the tree
Print the tree's postorder traversal as a single line of space-separated values.
4 3 6 5 2 1
The required result of the post-order traversal of the given binary tree is as above.