学习记录9

二叉树
// 定义二叉树节点类
class TreeNode {
int data;
TreeNode left;
TreeNode right;

public TreeNode(int data) {
    this.data = data;
    this.left = null;
    this.right = null;
}

}

// 定义二叉树类
class BinaryTree {
private TreeNode root;

public BinaryTree() {
    this.root = null;
}

// 前序遍历二叉树
public void preOrderTraversal(TreeNode node) {
    if (node != null) {
        System.out.print(node.data + " ");
        preOrderTraversal(node.left);
        preOrderTraversal(node.right);
    }
}

public static void main(String[] args) {
    BinaryTree tree = new BinaryTree();
    tree.root = new TreeNode(1);
    tree.root.left = new TreeNode(2);
    tree.root.right = new TreeNode(3);
    tree.root.left.left = new TreeNode(4);
    tree.root.left.right = new TreeNode(5);

    System.out.print("前序遍历结果: ");
    tree.preOrderTraversal(tree.root);
}

}