Binary Tree preorder, postorder and inorder with java

Question

I am studying my second semester in computer science, in my data structures class we are seeing binary trees with recursion. We have to make the preorder postorder and inorder t

Answer 1

There are some awsome binary tree visualizations online so you can understand it a little better but here are some images I use.

public void inOrderTraverseTree(Node focusNode) {
    if (focusNode != null) {
        // Traverse the left node
        inOrderTraverseTree(focusNode.leftChild);
        // Visit the currently focused on node
        System.out.println(focusNode);
        // Traverse the right node
        inOrderTraverseTree(focusNode.rightChild);
    }
}

public void postOrderTraverseTree(Node focusNode) {
    if (focusNode != null) {
        postOrderTraverseTree(focusNode.leftChild);
        postOrderTraverseTree(focusNode.rightChild);

        System.out.println(focusNode);
    }
}

public void preorderTraverseTree(Node focusNode) {
    if (focusNode != null) {
        System.out.println(focusNode);

        preorderTraverseTree(focusNode.leftChild);
        preorderTraverseTree(focusNode.rightChild);
    }
}