java循环

import java.util.Scanner;

public class Test1_16_6 {
    public static void main(String[] args) {
        Scanner in=new Scanner(System.in);
        for(int j=0;j<3;j++){
            System.out.println("请输入用户名");
            String user=in.next();
            System.out.println("请输入用户密码");
            String password=in.next();
            if(user.equals("zs")&&password.equals("12345")){                                    
                System.out.println("成功登陆");
                while(true){                
                    System.out.println("1.打印菱形");
                    System.out.println("2.打印正方形");
                    System.out.println("3.打印等边三角形");
                    System.out.println("4.打印等腰三角形");
                    System.out.println("5.打印直角三角形");                    
                    System.out.println("0.退出程序");    
                    System.out.println("请选择要执行的功能(0-5)");
                    String num=in.next();
                    switch(num){
                    case "1":
                        int no=1;
                        int k=0;
                        for (int i = 0; i < 5; i++) {
                            if(i<3){
                                for(int l=3-i;l>1;l--){
                                    System.out.print("  ");
                                }
                                for(int l=1;l<=i+no;l++){
                                    System.out.print("* ");
                                }
                            }else{

                                for(int l=i-2;l>=1;l--){
                                    System.out.print("  ");
                                }
                                for(int l=1;l<=i-k;l++){
                                    System.out.print("* ");                        
                                }
                                k+=3;
                            }
                            no++;
                            System.out.println();
                        }
                        break;
                    case "2":
                        for (int i = 0; i < 4; i++) {
                            for (int l = 0; l < 4; l++) {
                                System.out.print("* ");
                            }
                            System.out.println();
                        }
                        break;
                    case "3":
                        int n=1;
                        for (int i = 0; i < 4; i++) {
                            for (int l =4-i; l > 1; l--) {
                                System.out.print("  ");
                            }
                            for (int l = 1; l <= i+n; l++) {
                                System.out.print("* ");                
                            }
                            n++;
                            System.out.println();
                        }
                        break;
                    case "4":
                        for (int i = 0; i < 4; i++) {
                            for (int l = 0; l < 4-i; l++) {
                                System.out.print("* ");
                            }
                            System.out.println();
                        }
                        break;
                    case "5":
                        for (int i = 0; i < 4; i++) {
                            for (int l = 0; l <= i; l++) {
                                System.out.print("*");
                            }
                            System.out.println();
                        }
                        break;
                    case "0":
                        System.out.println("退出程序");
                        System.exit(0);
                    default:
                        System.out.println("错误的输入，请重新输入！");
                        
                    }
                    break;
                }
            }else if(j<2){
                System.out.println("账户或者密码输入错误请，重新输入(你还有"+(2-j)+"次机会");    
            }else{
                System.out.println("退出程序");    
            }
        }
    }
}