do while的循环

 1 package base.no5;
 2 
 3 import java.util.Scanner;
 4 
 5 public class Keyichongfushuru {
 6     public static void main(String[] args) {
 7         System.out.println("欢迎使用MyShopping管理系统\n");
 8         System.out.println("*******************************************");
 9         System.out.println("1.客户信息管理");
10         System.out.println("2.购物结算");
11         System.out.println("3.真情回馈");
12         System.out.println("4.注销");
13         System.out.println("*******************************************");
14         Scanner sc = new Scanner(System.in);
15         System.out.println("请选择，输入数字：");
16         double num = sc.nextInt();
17         int num1 = (int) num;
18         char ch =‘y‘;
19         do {
20             switch (num1) {
21             case 1:
22                 System.out.println("执行客户信息管理");
23                 ch =‘n‘;
24                 break;
25             case 2:
26                 System.out.println("执行购物结算");
27                 ch =‘n‘;
28                 break;
29             case 3:
30                 System.out.println("执行真情回馈");
31                 ch =‘n‘;
32                 break;
33             case 4:
34                 System.out.println("程序结束");
35                 ch =‘n‘;
36                 break;
37             default:
38                 System.out.println("输入错误重新输入：");
39                 num1 = sc.nextInt();
40                 break;
41             }
42         } while (ch == ‘y‘);
43     }
44 }