求助，如何结束SWITCH结构下的DO-WHILE循环

import java.util.Scanner;

public class liling33{
    public static void main (String[] args){

        
        
        System.out.println("\t\t\t\t欢迎使用我行我素购物管理系统>真情回馈\n\n");
        System.out.println("* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *");
        System.out.println("\t\t\t\t\t1. 幸运大放送\n\n");
        System.out.println("\t\t\t\t\t2. 幸运抽奖\n\n");
        System.out.println("\t\t\t\t\t3. 生日问候\n\n");

        System.out.println("请输入数字：\n\n");
        System.out.println("请选择，输入数字或按0返回上一级菜单\n\n");
        Scanner input =new Scanner (System.in);
        int num=input.nextInt();
        switch(num){
            case 0:
                System.out.println("执行返回上一级菜单\n\n");
                System.out.println("程序结束");
            case 1:

                System.out.println("执行幸运大放送\n\n");
                System.out.println("程序结束");
                break;
            case 2:
   
                System.out.println("执行幸运抽奖\n\n");


                    System.out.println("请输入4位会员号：\n");

                    int custNo=input.nextInt();
                    int qianwei=custNo/1000;
                    int baiwei=custNo%1000/100;
                    int shiwei=custNo%100/10;
                    int gewei=custNo%10;
                    int total;
                    total=qianwei+baiwei+shiwei+gewei;
                    if (total<=20){
                        System.out.println(custNo+"\t\t谢谢您的支持\n\n");
                        }else {
                        System.out.println(custNo+"\t\t是幸运客户，获精美MP3一个。\n\n");
                        }

                    String answer ="y";
                    System.out.println("\n是否继续(y/n)");
                    answer =input.next();
                    do{
                            if (total<=20){
                                System.out.println(custNo+"\t\t谢谢您的支持\n\n");
                            }else {
                                System.out.println(custNo+"\t\t是幸运客户，获精美MP3一个。\n\n");
                            }
                        

                    }while(answer.equals("y"));
                    System.out.println("程序结束");
                break;

            

                    

            case 3:
            
                System.out.println("执行生日问候\n\n");
                System.out.println("程序结束");
                break;

            default:
            
                System.out.println("输入错误。\n\n");
                System.out.println("程序结束");
                break;
               
        }

    }
}

各位大虾，我每次运行程序到：while(answer.equals("y"));按Y都会陷入死循环，请问：如何结束它并输入下一个？？？？？（按N会循环一次）


谢谢！！