关于二叉树的遍历

package study03;

public class TestBinaryTree {
    public static void main(String[] args) {
        //创建父节点
        BinaryTree root = new BinaryTree(1);
        BinaryTree tree2 = new BinaryTree(2);
        BinaryTree tree3 = new BinaryTree(3);
        //设置子节点的孩子节点
        root.setLeft(tree2);
        root.setRight(tree3);
        tree2.setLeft(new BinaryTree(4));
        tree2.setRight(new BinaryTree(5));
        tree3.setLeft(new BinaryTree(6));
        tree3.setRight(new BinaryTree(7));

        //创建测试对象
        TestBinaryTree t = new TestBinaryTree();
        t.preOrder(root);//调用前序遍历
        System.out.println("-------------");
        t.inOrder(root);//调用中序遍历
        System.out.println("-------------");
        t.lastOrder(root);//调用后序遍历

    }


    //前序遍历，其实每个遍历就只是输出的位置不一样
    private void preOrder(BinaryTree tree){
        System.out.print(tree.getValue()+" ");
        if (tree.getLeft()!=null){
            preOrder(tree.getLeft());
        }
        if (tree.getRight()!=null){
            preOrder(tree.getRight());
        }
    }
    //中序遍历
    private void inOrder(BinaryTree tree){
        if (tree.getLeft()!=null){
            inOrder(tree.getLeft());
        }
        System.out.print(tree.getValue()+" ");
        if (tree.getRight()!=null){
            inOrder(tree.getRight());
        }
    }

    //后序遍历
    private void lastOrder(BinaryTree tree){
        if (tree.getLeft()!=null){
            lastOrder(tree.getLeft());
        }
        if (tree.getRight()!=null){
            lastOrder(tree.getRight());
        }
        System.out.print(tree.getValue()+" ");
    }
}

package study03;

public class BinaryTree {
    private BinaryTree left;//存储左孩子节点的引用
    private BinaryTree right;//存储右孩子节点的引用
    private int value;//存储本身节点的值

    public BinaryTree(int value) {
        this.value = value;
    }

    public BinaryTree getLeft() {
        return left;
    }

    public void setLeft(BinaryTree left) {
        this.left = left;
    }

    public BinaryTree getRight() {
        return right;
    }

    public void setRight(BinaryTree right) {
        this.right = right;
    }

    public int getValue() {
        return value;
    }

    public void setValue(int value) {
        this.value = value;
    }
}