C++ experts!! Please help with this! Will rate

Using the binary_tree_node from code example, write a function to meet the following specification. Check as much of the precondition as possible. No recursion is needed. template void subswap(binary_tree_node* root_ptr)//Precondition: root_ptr is the root pointer of a non-empty binary tree.//Postcondition: The original left subtree has been moved and is now the right//subtree, and the original right subtree is now the left subtree.//Example original tree: Example new tree