上次多了两行

我的意思是说goto 跳到回头后为什么没停下要求要输入数据，而直接的循环上次输入的错识的提示.

public class RegisterDemo
{
    public RegisterDemo()
    {
        Register1 frame=new Register1();
        frame.setTitle("登录系统");
        frame.setVisible(true);
    }
    public static void main(String[] args)
    {
        new RegisterDemo();
    }
}
class Register extends JFrame
{
    /**
     * serialVersionUID
     */
    private static final long serialVersionUID = 1L;
    JLabel lblName,lblPassword;
    JTextField txtName;
    JPasswordField txtPass;
    JButton btnOk,btnExit;
    public Register1()
    {
        lblName=new JLabel("用户名");
        lblPassword=new JLabel("密码");
        txtName=new JTextField(20);
        txtPass=new JPasswordField(20);
        btnOk=new JButton("登录");
        btnExit=new JButton("退出");
        Box bv1=Box.createVerticalBox();
        bv1.add(lblName);
        bv1.add(Box.createRigidArea(new Dimension(8,8)));
        bv1.add(lblPassword);
        bv1.add(Box.createRigidArea(new Dimension(8,8)));
        Box bv2=Box.createVerticalBox();
        bv2.add(txtName);
        bv2.add(Box.createRigidArea(new Dimension(8,8)));
        bv2.add(txtPass);
        bv2.add(Box.createRigidArea(new Dimension(8,8)));
        Box bh=Box.createHorizontalBox();
        bh.add(bv1);
        bh.add(bv2);
        Box box=Box.createVerticalBox();
        box.add(bh);
        JPanel panel=new JPanel();
        panel.add(btnOk);
        panel.add(btnExit);
        box.add(panel);
        this.setLayout(new FlowLayout());
        this.add(box);
        this.setSize(300,140);
        this.setLocation(400,400);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        btnOk.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                String name=txtName.getText().trim();
                String pass=new String(txtPass.getPassword());
                if(name.equals("林月儿"))
                {
                    if(!pass.trim().equals("123"))
                    {
                        JOptionPane.showMessageDialog(null,"密码不正确！","警告!",JOptionPane.WARNING_MESSAGE);
                    }
                    else if(pass.trim().equals("123"))
                    {
                        String data="用户名:"+name+"\n";
                        data+="密码:"+pass.trim()+"\n";
                        JOptionPane.showMessageDialog(null, "登录成功!请核对:\n"+data,"提示",JOptionPane.INFORMATION_MESSAGE);
                    }
                }
                else
                {
                    JOptionPane.showMessageDialog(null,"该用户不存在！","警告!",JOptionPane.WARNING_MESSAGE);
                }
            }
        });
        btnExit.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                System.exit(0);
            }
        });
    }
}

嘻嘻，C#也来了。

#include <cstdio>
#include <cstring>
#include <conio.h>

const short K_ENTER = 0x0d;

const char* Correct_Password = "1a2b3c";
const size_t Max_Password_Length = 10;

const char* Get_Password(char* str)
{
    size_t index = 0;

    printf_s("請輸入密碼: ");
    while (index < Max_Password_Length)
    {
        int ch = _getch();
        if (ch == K_ENTER)
        {
            break;
        }
        str[index++] = ch;
        putchar('*');
    }
    str[index] = '\0';

    putchar('\n');

    return str;
}

int main(void)
{
    char password[Max_Password_Length + 1];
    size_t count = 0;

    while (count++ < 2)
    {
        printf_s("您輸入的密碼是: %s\n", Get_Password(password));
        if (strcmp(password, Correct_Password) == 0)
        {
            printf_s("密碼正確!\n");
        }
    }

    printf_s("按任意鍵結束程序...");
    _getch();
    return 0;
}

我的意思是说goto 跳到回头后为什么没停下要求要输入数据，而直接的循环上次输入的错识的提示.不是要代码，只不不明白为什么?

赞
实战的风格

T版好兴致

老生常谈，scanf()在遇到非法输入数据后，若不清空输入缓冲区数据，则那些非法数据始终堵塞在输入流中，让后续的scanf()反覆读入非法数据从而死循环。这个问题坛上都不知回答过多少次，你不去看论坛历史帖子总问，大家不答你也是这个原因。

谢谢解答，