Binary Tree Traversals - Implementation in Java

void preorderT(Node root){
    if (root==null) return;

    root.visit();
    preorderT(root.left);
    preorderT(root.right);
}

void postorderT(Node root){
    if (root==null) return;

    preorderT(root.left);
    preorderT(root.right);
    root.visit();
}

void inorderT(Node root){
    if (root==null) return;

    preorderT(root.left);
    root.visit();
    preorderT(root.right);
}

/* Non-Recursive Implementation of Preorder Traversal */

public class Stack{
    public void push(Node node) {...}
    public Node pop() {...}
    public boolean isEmpty() {...}
}

void preorderTNR(Node root){
    Stack stack=new Stack();
    stack.push(root);

    //Note that I had forgotten the () after isEmpty in the video
    while(!stack.isEmpty()){
        Node n=stack.pop();

        n.visit();
        if (n.right!=null)stack.push(n.right);
        if (n.left!=null)stack.push(n.left);
    }
}