switch (type) { case 'enter' || 'confirm': break;} 这是写错在哪

里面？

这段代码写错在了 case 'enter' || 'confirm' 这一行，因为 || 运算符不能用于 case 语句中，应该写成两个 case 分别处理 'enter' 和 'confirm'。正确的写法应该是：

switch (type) {
case 'enter':
case 'confirm':
break;
}

相关问题

用c语言写一个贪吃蛇游戏”的说明如下：（参照演示程序和源程序框架）启动程序时，输入的用户名如果以前没有，则系统自动完成注册，如果有，则进行密码比较以判断是否允许登录。用户名将用于英雄榜中。

好的，这是一个比较复杂的问题。首先，你需要了解贪吃蛇游戏的规则和逻辑，然后你需要学习如何使用C语言进行编程。

以下是一个简单的贪吃蛇游戏的源程序框架，可以帮助你开始编写你自己的贪吃蛇游戏：

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <time.h>

#define MAX_X 20
#define MAX_Y 20

enum direction {UP, DOWN, LEFT, RIGHT};

struct snake {
  int x;
  int y;
  struct snake *next;
};

struct snake *head, *tail;
int food_x, food_y;
enum direction dir = RIGHT;
int score = 0;
char username[20];

void init_game();
void init_snake();
void init_food();
void display();
void update();
void game_over();
void save_score();
int check_collision(int x, int y);
void register_user();
void login();

int main() {
  int choice;
  printf("Welcome to Snake Game!\n");
  printf("1. Register\n");
  printf("2. Login\n");
  printf("Enter your choice: ");
  scanf("%d", &choice);
  if (choice == 1) {
    register_user();
  } else if (choice == 2) {
    login();
  } else {
    printf("Invalid choice!\n");
    exit(0);
  }
  init_game();
  while (1) {
    display();
    update();
    Sleep(100);
  }
  return 0;
}

void init_game() {
  srand(time(NULL));
  init_snake();
  init_food();
}

void init_snake() {
  head = (struct snake*) malloc(sizeof(struct snake));
  tail = (struct snake*) malloc(sizeof(struct snake));
  head->x = 3;
  head->y = 1;
  head->next = tail;
  tail->x = 1;
  tail->y = 1;
  tail->next = NULL;
}

void init_food() {
  food_x = rand() % MAX_X + 1;
  food_y = rand() % MAX_Y + 1;
}

void display() {
  system("cls");
  printf("Score: %d\n", score);
  for (int i = 0; i < MAX_X; i++) {
    for (int j = 0; j < MAX_Y; j++) {
      if (i == head->x && j == head->y) {
        printf("O");
      } else if (i == food_x && j == food_y) {
        printf("*");
      } else {
        int found = 0;
        struct snake *ptr = head->next;
        while (ptr != tail) {
          if (ptr->x == i && ptr->y == j) {
            printf("o");
            found = 1;
            break;
          }
          ptr = ptr->next;
        }
        if (!found) {
          printf(" ");
        }
      }
    }
    printf("\n");
  }
}

void update() {
  int new_x = head->x, new_y = head->y;
  switch (dir) {
    case UP:
      new_x--;
      break;
    case DOWN:
      new_x++;
      break;
    case LEFT:
      new_y--;
      break;
    case RIGHT:
      new_y++;
      break;
  }
  if (check_collision(new_x, new_y)) {
    game_over();
    return;
  }
  struct snake *new_head = (struct snake*) malloc(sizeof(struct snake));
  new_head->x = new_x;
  new_head->y = new_y;
  new_head->next = head;
  head = new_head;
  if (new_x == food_x && new_y == food_y) {
    score++;
    init_food();
  } else {
    struct snake *ptr = head;
    while (ptr->next != tail) {
      ptr = ptr->next;
    }
    struct snake *old_tail = tail;
    tail = ptr;
    free(old_tail);
  }
}

void game_over() {
  printf("Game over! Your score is %d.\n", score);
  save_score();
  exit(0);
}

void save_score() {
  FILE *fp;
  fp = fopen("high_scores.txt", "a");
  fprintf(fp, "%s %d\n", username, score);
  fclose(fp);
}

int check_collision(int x, int y) {
  if (x < 0 || x >= MAX_X || y < 0 || y >= MAX_Y) {
    return 1;
  }
  struct snake *ptr = head->next;
  while (ptr != tail) {
    if (ptr->x == x && ptr->y == y) {
      return 1;
    }
    ptr = ptr->next;
  }
  return 0;
}

void register_user() {
  char password[20], confirm[20];
  FILE *fp;
  fp = fopen("users.txt", "a+");
  printf("Enter your username: ");
  scanf("%s", username);
  while (!feof(fp)) {
    char name[20], pass[20];
    fscanf(fp, "%s %s", name, pass);
    if (strcmp(username, name) == 0) {
      printf("Username already exists!\n");
      fclose(fp);
      exit(0);
    }
  }
  printf("Enter your password: ");
  scanf("%s", password);
  printf("Confirm your password: ");
  scanf("%s", confirm);
  if (strcmp(password, confirm) != 0) {
    printf("Passwords do not match!\n");
    fclose(fp);
    exit(0);
  }
  fprintf(fp, "%s %s\n", username, password);
  fclose(fp);
}

void login() {
  char password[20];
  FILE *fp;
  fp = fopen("users.txt", "r");
  printf("Enter your username: ");
  scanf("%s", username);
  while (!feof(fp)) {
    char name[20], pass[20];
    fscanf(fp, "%s %s", name, pass);
    if (strcmp(username, name) == 0) {
      printf("Enter your password: ");
      scanf("%s", password);
      if (strcmp(password, pass) != 0) {
        printf("Incorrect password!\n");
        fclose(fp);
        exit(0);
      }
      fclose(fp);
      return;
    }
  }
  printf("Username does not exist!\n");
  fclose(fp);
  exit(0);
}

这个程序包含了很多功能，包括注册、登录、保存分数、检查碰撞等等。你可以按照程序框架，编写自己的贪吃蛇游戏程序。

设计一个用户登陆注册界面，要求用户信息用一个文本文件保存，当该文件不存在，则提示用户注册，将用户的信息写入文件，如果文件存在则进行密码核对，如果密码正确则进入系统，该系统使用随机函数生成四则运算的出题界面，用户可以对出题给出答案程序能够自动判断对错，先期设定运算题型，数据大小，题目数量，最后根据批改给出测试成绩，写出代码

以下是一个基本的Java代码实现：

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;

import javax.swing.*;

public class LoginRegisterPanel extends JPanel {
    private JTextField usernameField;
    private JPasswordField passwordField;
    private JPasswordField confirmPasswordField;
    private JButton loginButton;
    private JButton registerButton;
    private JLabel statusLabel;

    private File usersFile;
    private Map<String, String> users;

    public LoginRegisterPanel(File usersFile) {
        this.usersFile = usersFile;
        users = new HashMap<>();
        loadUsers();

        setLayout(new BorderLayout());

        JPanel inputPanel = new JPanel(new GridLayout(3, 2, 5, 5));
        inputPanel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
        inputPanel.add(new JLabel("Username:"));
        inputPanel.add(usernameField = new JTextField());
        inputPanel.add(new JLabel("Password:"));
        inputPanel.add(passwordField = new JPasswordField());
        inputPanel.add(new JLabel("Confirm Password:"));
        inputPanel.add(confirmPasswordField = new JPasswordField());
        add(inputPanel, BorderLayout.CENTER);

        JPanel buttonPanel = new JPanel(new GridLayout(1, 2, 5, 5));
        buttonPanel.setBorder(BorderFactory.createEmptyBorder(0, 10, 10, 10));
        buttonPanel.add(loginButton = new JButton("Login"));
        loginButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (checkUser()) {
                    statusLabel.setText("Login success!");
                } else {
                    statusLabel.setText("Invalid username or password!");
                }
            }
        });
        buttonPanel.add(registerButton = new JButton("Register"));
        registerButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (registerUser()) {
                    statusLabel.setText("Register success!");
                } else {
                    statusLabel.setText("Username already exists!");
                }
            }
        });
        add(buttonPanel, BorderLayout.SOUTH);

        add(statusLabel = new JLabel("Enter username and password to login or register."), BorderLayout.NORTH);
    }

    private void loadUsers() {
        if (!usersFile.exists()) {
            try {
                usersFile.createNewFile();
            } catch (IOException e) {
                e.printStackTrace();
                return;
            }
        }
        try (Scanner scanner = new Scanner(usersFile)) {
            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();
                String[] fields = line.split(",");
                if (fields.length == 2) {
                    users.put(fields[0], fields[1]);
                }
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }

    private void saveUsers() {
        try (PrintWriter writer = new PrintWriter(usersFile)) {
            for (Map.Entry<String, String> entry : users.entrySet()) {
                writer.println(entry.getKey() + "," + entry.getValue());
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }

    private boolean checkUser() {
        String username = usernameField.getText();
        String password = new String(passwordField.getPassword());
        if (users.containsKey(username) && users.get(username).equals(password)) {
            return true;
        } else {
            return false;
        }
    }

    private boolean registerUser() {
        String username = usernameField.getText();
        String password = new String(passwordField.getPassword());
        String confirmPassword = new String(confirmPasswordField.getPassword());
        if (username.isEmpty() || password.isEmpty() || !password.equals(confirmPassword)) {
            return false;
        }
        if (users.containsKey(username)) {
            return false;
        }
        users.put(username, password);
        saveUsers();
        return true;
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Login/Register");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setContentPane(new LoginRegisterPanel(new File("users.txt")));
        frame.pack();
        frame.setVisible(true);
    }
}

这是一个登陆注册界面的示例，用户信息保存在文件`users.txt`中，采用逗号分隔的用户名和密码格式。其中`loadUsers()`方法用于从文件中读取用户信息，`saveUsers()`方法用于将用户信息保存到文件中，`checkUser()`方法用于核对用户密码，`registerUser()`方法用于注册新用户。

接下来是四则运算的实现：

import java.awt.*;
import java.awt.event.*;
import java.util.Random;

import javax.swing.*;

public class MathQuizPanel extends JPanel {
    private JLabel questionLabel;
    private JTextField answerField;
    private JButton submitButton;
    private JLabel resultLabel;

    private int num1;
    private int num2;
    private char operator;
    private int answer;

    private int correctCount;
    private int questionCount;

    public MathQuizPanel() {
        setLayout(new BorderLayout());

        JPanel inputPanel = new JPanel(new GridLayout(2, 2, 5, 5));
        inputPanel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
        inputPanel.add(new JLabel("Question:"));
        inputPanel.add(questionLabel = new JLabel());
        inputPanel.add(new JLabel("Answer:"));
        inputPanel.add(answerField = new JTextField());
        add(inputPanel, BorderLayout.CENTER);

        JPanel buttonPanel = new JPanel(new GridLayout(1, 2, 5, 5));
        buttonPanel.setBorder(BorderFactory.createEmptyBorder(0, 10, 10, 10));
        buttonPanel.add(submitButton = new JButton("Submit"));
        submitButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                try {
                    int userAnswer = Integer.parseInt(answerField.getText().trim());
                    if (userAnswer == answer) {
                        resultLabel.setText("Correct!");
                        correctCount++;
                    } else {
                        resultLabel.setText("Wrong! The answer is " + answer);
                    }
                    questionCount++;
                    generateQuestion();
                } catch (NumberFormatException ex) {
                    resultLabel.setText("Please enter a number.");
                }
            }
        });
        buttonPanel.add(resultLabel = new JLabel(" "));
        add(buttonPanel, BorderLayout.SOUTH);

        generateQuestion();
    }

    private void generateQuestion() {
        Random random = new Random();
        num1 = random.nextInt(100);
        num2 = random.nextInt(100);
        operator = "+-*/".charAt(random.nextInt(4));
        switch (operator) {
            case '+':
                answer = num1 + num2;
                break;
            case '-':
                answer = num1 - num2;
                break;
            case '*':
                answer = num1 * num2;
                break;
            case '/':
                answer = num1 / num2;
                break;
        }
        questionLabel.setText(String.format("%d %c %d = ", num1, operator, num2));
        answerField.setText("");
        resultLabel.setText(" ");
    }

    public void reset() {
        correctCount = 0;
        questionCount = 0;
        generateQuestion();
    }

    public int getCorrectCount() {
        return correctCount;
    }

    public int getQuestionCount() {
        return questionCount;
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Math Quiz");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        MathQuizPanel panel = new MathQuizPanel();
        frame.setContentPane(panel);
        frame.pack();
        frame.setVisible(true);
    }
}

这是一个四则运算出题界面的示例，使用随机函数生成两个随机数和一个随机运算符，并计算出正确答案。用户输入答案后，程序自动判断对错，并计算答对的题目数量和总题数。`reset()`方法用于重新开始出题，`getCorrectCount()`和`getQuestionCount()`方法用于获取答对的题目数量和总题数。

最后是主程序的实现：

import java.awt.*;
import java.awt.event.*;
import java.io.File;

import javax.swing.*;

public class MathQuizApp {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Math Quiz");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        LoginRegisterPanel loginRegisterPanel = new LoginRegisterPanel(new File("users.txt"));
        MathQuizPanel mathQuizPanel = new MathQuizPanel();

        JButton startButton = new JButton("Start Quiz");
        startButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (loginRegisterPanel.checkUser()) {
                    loginRegisterPanel.setVisible(false);
                    mathQuizPanel.reset();
                    mathQuizPanel.setVisible(true);
                } else {
                    JOptionPane.showMessageDialog(frame, "Invalid username or password!");
                }
            }
        });

        JButton backButton = new JButton("Back");
        backButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                loginRegisterPanel.setVisible(true);
                mathQuizPanel.setVisible(false);
            }
        });

        JPanel buttonPanel = new JPanel(new GridLayout(1, 2, 5, 5));
        buttonPanel.setBorder(BorderFactory.createEmptyBorder(0, 10, 10, 10));
        buttonPanel.add(startButton);
        buttonPanel.add(backButton);

        JPanel contentPanel = new JPanel(new CardLayout());
        contentPanel.add(loginRegisterPanel, "loginRegister");
        contentPanel.add(mathQuizPanel, "mathQuiz");

        frame.setContentPane(new JPanel(new BorderLayout()));
        frame.getContentPane().add(contentPanel, BorderLayout.CENTER);
        frame.getContentPane().add(buttonPanel, BorderLayout.SOUTH);

        frame.pack();
        frame.setVisible(true);
    }
}

这是一个整合登陆注册界面和四则运算出题界面的示例，使用`CardLayout`来切换不同的界面。用户登陆成功后进入四则运算出题界面，用户可以进行答题，答题完成后返回登陆注册界面。