import java.util.*;

class Main
{
public static void main(String[] args)
{
int sel;
int num;

Scanner keyboard = new Scanner(System.in);

tree object = new tree();

while(true)
{
System.out.println();
System.out.println("*********메뉴*********");
System.out.println();
System.out.println("1. 추가");
System.out.println("2. 출력");
System.out.println("3. 전위탐방");
System.out.println("4. 중위탐방");
System.out.println("5. 후위탐방");
System.out.println("6. 종료");
System.out.println();
System.out.print("메뉴를 선택해주세요 (1~6) : ");
sel = keyboard.nextInt();
System.out.println();

switch(sel)