Question

Implement a method (in java) to print all the element of a binary search tree in pre-order traversal order. (CANNOT TAKE A PARAMETER) Thank you!

public void printTree()

{

//chegg code here only!

}

Answer 1

//Iterative preorder traversal

//Java program

public void printTree() {
  
// if tree is empty
if (root == null) {
return;
}
  
// Create an empty stack and push root to it
Stack<Node> stack = new Stack<Node>();
stack.push(root);
  
while (stack.empty() == false) {
// Pop the top item from stack and print it
Node currentnode = stack.peek();
System.out.print(currentnode.data + " ");
stack.pop();
  
// Push right and left children of the popped node to stack
if (currentnode.right != null) {
stack.push(currentnode.right);
}
if (currentnode.left != null) {
stack.push(currentnode.left);
}
}
}