static bool containsControlCharacter( const char* str ) { while ( *str ) { if ( isControlCharacter( *(str++) ) ) return true; } return false; }

这个问题属于技术问题，我可以回答。这是一个C++中判断字符串中是否包含控制字符的函数，函数中的isControlCharacter()是一个用于判断字符是否为控制字符的函数。该函数会遍历字符串中的每个字符，如果找到了控制字符，则返回true，如果整个字符串都没有控制字符，则返回false。

相关问题

UEC++编写实现MQTT协议

MQTT（Message Queuing Telemetry Transport）是一个轻量级的、基于发布/订阅模式的通讯协议，被广泛应用于物联网等领域。下面是一个使用UEC++编写实现MQTT协议的示例：

#include <iostream>
#include <string>
#include <cstring>
#include <map>
#include <vector>

using namespace std;

// 定义MQTT消息类型
enum MqttMessageType {
  CONNECT = 1,
  CONNACK,
  PUBLISH,
  PUBACK,
  PUBREC,
  PUBREL,
  PUBCOMP,
  SUBSCRIBE,
  SUBACK,
  UNSUBSCRIBE,
  UNSUBACK,
  PINGREQ,
  PINGRESP,
  DISCONNECT
};

// 定义MQTT连接状态
enum MqttConnectStatus {
  CONNECT_ACCEPTED = 0,
  CONNECT_REFUSED_PROTOCOL,
  CONNECT_REFUSED_ID,
  CONNECT_REFUSED_SERVER,
  CONNECT_REFUSED_USER,
  CONNECT_REFUSED_PWD
};

// 定义MQTT消息结构体
struct MqttMessage {
  MqttMessageType type;
  bool dup;
  int qos;
  bool retain;
  int length;
  string topic;
  string payload;
  int packet_id;
  map<string, string> properties;
};

// 定义MQTT连接结构体
struct MqttConnect {
  string protocol_name;
  int protocol_version;
  bool clean_session;
  bool will_flag;
  int will_qos;
  bool will_retain;
  string will_topic;
  string will_message;
  string client_id;
  string username;
  string password;
  map<string, string> properties;
};

// 定义MQTT客户端类
class MqttClient {
public:
  MqttClient(const string& broker_url, int broker_port);
  ~MqttClient();
  bool connect(const MqttConnect& connect);
  bool publish(const MqttMessage& message);
  bool subscribe(const vector<string>& topics);
  bool unsubscribe(const vector<string>& topics);
  void disconnect();
private:
  bool send_message(const MqttMessage& message);
  bool read_message(MqttMessage& message);
  string broker_url_;
  int broker_port_;
  int socket_fd_;
  int packet_id_;
};

// 构造函数
MqttClient::MqttClient(const string& broker_url, int broker_port)
  : broker_url_(broker_url), broker_port_(broker_port), socket_fd_(-1), packet_id_(1) {}

// 析构函数
MqttClient::~MqttClient() {
  disconnect();
}

// 连接到MQTT服务器
bool MqttClient::connect(const MqttConnect& connect) {
  // 建立TCP连接
  socket_fd_ = socket(AF_INET, SOCK_STREAM, 0);
  if (socket_fd_ < 0) {
    cerr << "Failed to create socket." << endl;
    return false;
  }
  struct sockaddr_in broker_addr;
  memset(&broker_addr, 0, sizeof(broker_addr));
  broker_addr.sin_family = AF_INET;
  broker_addr.sin_port = htons(broker_port_);
  broker_addr.sin_addr.s_addr = inet_addr(broker_url_.c_str());
  if (connect(socket_fd_, (struct sockaddr*)&broker_addr, sizeof(broker_addr)) < 0) {
    cerr << "Failed to connect to broker." << endl;
    return false;
  }
  // 发送CONNECT消息
  MqttMessage message;
  message.type = CONNECT;
  message.qos = 0;
  message.properties["protocol_name"] = connect.protocol_name;
  message.properties["protocol_version"] = to_string(connect.protocol_version);
  message.properties["clean_session"] = connect.clean_session ? "1" : "0";
  message.properties["client_id"] = connect.client_id;
  message.properties["will_flag"] = connect.will_flag ? "1" : "0";
  message.properties["will_qos"] = to_string(connect.will_qos);
  message.properties["will_retain"] = connect.will_retain ? "1" : "0";
  message.properties["will_topic"] = connect.will_topic;
  message.properties["will_message"] = connect.will_message;
  message.properties["username"] = connect.username;
  message.properties["password"] = connect.password;
  message.properties.insert(connect.properties.begin(), connect.properties.end());
  if (!send_message(message)) {
    cerr << "Failed to send CONNECT message." << endl;
    return false;
  }
  // 读取CONNACK消息
  MqttMessage connack;
  if (!read_message(connack) || connack.type != CONNACK) {
    cerr << "Failed to receive CONNACK message." << endl;
    return false;
  }
  if (connack.properties["connect_status"] != to_string(CONNECT_ACCEPTED)) {
    cerr << "Connect refused: " << connack.properties["connect_status"] << endl;
    return false;
  }
  return true;
}

// 发布MQTT消息
bool MqttClient::publish(const MqttMessage& message) {
  // 发送PUBLISH消息
  MqttMessage publish_msg = message;
  publish_msg.type = PUBLISH;
  publish_msg.dup = false;
  publish_msg.packet_id = packet_id_++;
  if (!send_message(publish_msg)) {
    cerr << "Failed to send PUBLISH message." << endl;
    return false;
  }
  // 读取PUBACK消息
  if (message.qos == 1) {
    MqttMessage puback;
    if (!read_message(puback) || puback.type != PUBACK || puback.packet_id != publish_msg.packet_id) {
      cerr << "Failed to receive PUBACK message." << endl;
      return false;
    }
  }
  return true;
}

// 订阅MQTT主题
bool MqttClient::subscribe(const vector<string>& topics) {
  // 构造SUBSCRIBE消息
  MqttMessage message;
  message.type = SUBSCRIBE;
  message.qos = 1;
  message.packet_id = packet_id_++;
  for (auto topic : topics) {
    message.properties["topic"] = topic;
    message.properties["qos"] = "1";
  }
  if (!send_message(message)) {
    cerr << "Failed to send SUBSCRIBE message." << endl;
    return false;
  }
  // 读取SUBACK消息
  MqttMessage suback;
  if (!read_message(suback) || suback.type != SUBACK || suback.packet_id != message.packet_id) {
    cerr << "Failed to receive SUBACK message." << endl;
    return false;
  }
  return true;
}

// 取消订阅MQTT主题
bool MqttClient::unsubscribe(const vector<string>& topics) {
  // 构造UNSUBSCRIBE消息
  MqttMessage message;
  message.type = UNSUBSCRIBE;
  message.qos = 1;
  message.packet_id = packet_id_++;
  for (auto topic : topics) {
    message.properties["topic"] = topic;
  }
  if (!send_message(message)) {
    cerr << "Failed to send UNSUBSCRIBE message." << endl;
    return false;
  }
  // 读取UNSUBACK消息
  MqttMessage unsuback;
  if (!read_message(unsuback) || unsuback.type != UNSUBACK || unsuback.packet_id != message.packet_id) {
    cerr << "Failed to receive UNSUBACK message." << endl;
    return false;
  }
  return true;
}

// 断开MQTT连接
void MqttClient::disconnect() {
  if (socket_fd_ >= 0) {
    MqttMessage message;
    message.type = DISCONNECT;
    send_message(message);
    close(socket_fd_);
    socket_fd_ = -1;
  }
}

// 发送MQTT消息
bool MqttClient::send_message(const MqttMessage& message) {
  // 构造消息头
  char header[5];
  int pos = 0;
  header[pos++] = (message.type << 4) | (message.dup << 3) | (message.qos << 1) | message.retain;
  do {
    uint8_t digit = message.length % 128;
    message.length /= 128;
    if (message.length > 0) {
      digit |= 0x80;
    }
    header[pos++] = digit;
  } while (message.length > 0);
  // 发送消息头
  if (write(socket_fd_, header, pos) != pos) {
    return false;
  }
  // 发送消息体
  if (write(socket_fd_, message.topic.c_str(), message.topic.length()) != message.topic.length() ||
      (message.qos > 0 && write(socket_fd_, &message.packet_id, sizeof(message.packet_id)) != sizeof(message.packet_id)) ||
      write(socket_fd_, message.payload.c_str(), message.payload.length()) != message.payload.length()) {
    return false;
  }
  return true;
}

// 读取MQTT消息
bool MqttClient::read_message(MqttMessage& message) {
  // 读取消息头
  char header[5];
  int pos = 0;
  while (pos < 2) {
    int ret = read(socket_fd_, header + pos, 2 - pos);
    if (ret <= 0) {
      return false;
    }
    pos += ret;
  }
  message.type = static_cast<MqttMessageType>((header[0] & 0xf0) >> 4);
  message.dup = (header[0] & 0x08) != 0;
  message.qos = (header[0] & 0x06) >> 1;
  message.retain = (header[0] & 0x01) != 0;
  message.length = 0;
  for (int i = 1; i < pos; ++i) {
    message.length = (message.length << 7) | (header[i] & 0x7f);
    if ((header[i] & 0x80) == 0) {
      break;
    }
  }
  // 读取消息体
  int payload_len = message.length;
  if (message.qos > 0) {
    payload_len -= sizeof(message.packet_id);
  }
  char* payload_buf = new char[payload_len];
  pos = 0;
  while (pos < payload_len) {
    int ret = read(socket_fd_, payload_buf + pos, payload_len - pos);
    if (ret <= 0) {
      delete[] payload_buf;
      return false;
    }
    pos += ret;
  }
  message.topic = string(payload_buf, payload_len);
  if (message.qos > 0) {
    memcpy(&message.packet_id, payload_buf + payload_len, sizeof(message.packet_id));
    message.payload = string(payload_buf + payload_len + sizeof(message.packet_id), message.length - payload_len - sizeof(message.packet_id));
  } else {
    message.payload = string(payload_buf + payload_len, message.length - payload_len);
  }
  delete[] payload_buf;
  return true;
}

int main() {
  MqttConnect connect;
  connect.protocol_name = "MQTT";
  connect.protocol_version = 4;
  connect.clean_session = true;
  connect.client_id = "test_client";
  MqttClient client("localhost", 1883);
  if (client.connect(connect)) {
    MqttMessage message;
    message.qos = 1;
    message.topic = "test_topic";
    message.payload = "hello world";
    client.publish(message);
    client.subscribe({"test_topic"});
    client.unsubscribe({"test_topic"});
    client.disconnect();
  }
  return 0;
}

这段代码实现了MQTT客户端的基本功能，包括连接到MQTT服务器、发布消息、订阅主题和取消订阅主题等。其中，send_message函数用于发送MQTT消息，read_message函数用于读取MQTT消息。MQTT消息的格式和消息头的解析方式参考MQTT协议规范。

用C + +与easyX写一个小游戏

好的，我们可以写一个飞机大战小游戏。

首先，我们需要下载并安装 EasyX，它是一款简单易用的图形库，可以帮助我们快速地实现图形界面的操作。

接下来，我们可以开始编写代码。首先是头文件的引入和命名空间的声明：

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

using namespace std;

然后是一些常量的定义：

const int WIDTH = 480; // 窗口宽度
const int HEIGHT = 700; // 窗口高度
const int BULLET_NUM = 100; // 子弹数量
const int ENEMY_NUM = 20; // 敌机数量
const int ENEMY_SPEED = 3; // 敌机速度
const int BULLET_SPEED = 10; // 子弹速度
const int HERO_SPEED = 5; // 英雄飞机速度
const int HERO_HP = 3; // 英雄飞机生命值

接下来是一些全局变量的定义：

IMAGE bg; // 背景图
IMAGE hero; // 英雄飞机图
IMAGE enemy; // 敌机图
IMAGE bullet; // 子弹图
IMAGE boom; // 爆炸图
int hero_x, hero_y; // 英雄飞机的坐标
int hero_w, hero_h; // 英雄飞机的宽度和高度
int enemy_x[ENEMY_NUM], enemy_y[ENEMY_NUM]; // 敌机的坐标
int enemy_hp[ENEMY_NUM]; // 敌机的生命值
int enemy_w, enemy_h; // 敌机的宽度和高度
int bullet_x[BULLET_NUM], bullet_y[BULLET_NUM]; // 子弹的坐标
int bullet_w, bullet_h; // 子弹的宽度和高度
int boom_x, boom_y; // 爆炸效果的坐标
int boom_w, boom_h; // 爆炸效果的宽度和高度
int score = 0; // 得分
int hp = HERO_HP; // 英雄飞机生命值
bool is_game_over = false; // 游戏是否结束

然后是一些函数的声明：

void init(); // 初始化函数
void draw(); // 绘制函数
void move(); // 移动函数
void shoot(); // 射击函数
void hit(); // 碰撞检测函数
void game_over(); // 游戏结束处理函数

接下来是主函数的实现：

int main()
{
    initgraph(WIDTH, HEIGHT); // 初始化图形界面
    init(); // 初始化游戏
    while(!is_game_over) // 游戏循环
    {
        draw(); // 绘制游戏
        move(); // 移动游戏
        shoot(); // 射击子弹
        hit(); // 碰撞检测
        Sleep(30); // 防止游戏速度过快
        if(hp <= 0) // 生命值为0，游戏结束
        {
            game_over(); // 处理游戏结束
        }
    }
    getchar();
    closegraph(); // 关闭图形界面
    return 0;
}

接下来是各个函数的实现：

初始化函数：

void init()
{
    srand(time(NULL)); // 设置随机数种子
    loadimage(&bg, "bg.jpg"); // 载入背景图
    loadimage(&hero, "hero.png"); // 载入英雄飞机图
    loadimage(&enemy, "enemy.png"); // 载入敌机图
    loadimage(&bullet, "bullet.png"); // 载入子弹图
    loadimage(&boom, "boom.png"); // 载入爆炸图
    hero_x = (WIDTH - getwidth(&hero)) / 2; // 英雄飞机初始位置
    hero_y = HEIGHT - getheight(&hero) - 50;
    hero_w = getwidth(&hero); // 英雄飞机大小
    hero_h = getheight(&hero);
    enemy_w = getwidth(&enemy); // 敌机大小
    enemy_h = getheight(&enemy);
    bullet_w = getwidth(&bullet); // 子弹大小
    bullet_h = getheight(&bullet);
    for(int i = 0; i < ENEMY_NUM; i++) // 敌机初始位置和生命值
    {
        enemy_x[i] = rand() % (WIDTH - enemy_w);
        enemy_y[i] = rand() % (HEIGHT / 2) - HEIGHT;
        enemy_hp[i] = 1;
    }
}

绘制函数：

void draw()
{
    putimage(0, 0, &bg); // 绘制背景图
    putimage(hero_x, hero_y, &hero); // 绘制英雄飞机
    for(int i = 0; i < ENEMY_NUM; i++) // 绘制敌机
    {
        if(enemy_hp[i] > 0)
        {
            putimage(enemy_x[i], enemy_y[i], &enemy);
        }
    }
    for(int i = 0; i < BULLET_NUM; i++) // 绘制子弹
    {
        if(bullet_y[i] > 0)
        {
            putimage(bullet_x[i], bullet_y[i], &bullet);
        }
    }
    settextcolor(WHITE); // 绘制得分和生命值
    char str[50];
    sprintf(str, "Score: %d", score);
    outtextxy(20, 20, str);
    sprintf(str, "HP: %d", hp);
    outtextxy(WIDTH - 80, 20, str);
    if(is_game_over) // 绘制爆炸效果
    {
        putimage(boom_x, boom_y, &boom);
    }
}

移动函数：

void move()
{
    char c = getch(); // 获取键盘输入
    switch(c)
    {
        case 'a': // 左移
            hero_x -= HERO_SPEED;
            break;
        case 'd': // 右移
            hero_x += HERO_SPEED;
            break;
        case 'w': // 上移
            hero_y -= HERO_SPEED;
            break;
        case 's': // 下移
            hero_y += HERO_SPEED;
            break;
    }
    if(hero_x < 0) // 边界检测
    {
        hero_x = 0;
    }
    if(hero_x > WIDTH - hero_w)
    {
        hero_x = WIDTH - hero_w;
    }
    if(hero_y < 0)
    {
        hero_y = 0;
    }
    if(hero_y > HEIGHT - hero_h)
    {
        hero_y = HEIGHT - hero_h;
    }
    for(int i = 0; i < ENEMY_NUM; i++) // 敌机移动
    {
        if(enemy_hp[i] > 0)
        {
            enemy_y[i] += ENEMY_SPEED;
        }
        if(enemy_y[i] > HEIGHT) // 敌机重新出现
        {
            enemy_x[i] = rand() % (WIDTH - enemy_w);
            enemy_y[i] = rand() % (HEIGHT / 2) - HEIGHT;
            enemy_hp[i] = 1;
        }
    }
    for(int i = 0; i < BULLET_NUM; i++) // 子弹移动
    {
        if(bullet_y[i] > 0)
        {
            bullet_y[i] -= BULLET_SPEED;
        }
    }
}

射击函数：

void shoot()
{
    static int count = 0;
    count++;
    if(count > 10) // 控制子弹发射速度
    {
        count = 0;
        for(int i = 0; i < BULLET_NUM; i++)
        {
            if(bullet_y[i] <= 0) // 子弹未使用，进行发射
            {
                bullet_x[i] = hero_x + hero_w / 2 - bullet_w / 2;
                bullet_y[i] = hero_y - bullet_h;
                break;
            }
        }
    }
}

碰撞检测函数：

void hit()
{
    for(int i = 0; i < ENEMY_NUM; i++) // 子弹和敌机的碰撞检测
    {
        for(int j = 0; j < BULLET_NUM; j++)
        {
            if(bullet_y[j] > 0 && enemy_hp[i] > 0 &&
               bullet_x[j] > enemy_x[i] - bullet_w &&
               bullet_x[j] < enemy_x[i] + enemy_w &&
               bullet_y[j] > enemy_y[i] - bullet_h &&
               bullet_y[j] < enemy_y[i] + enemy_h)
            {
                enemy_hp[i]--; // 减少敌机生命值
                bullet_y[j] = -1; // 子弹消失
                if(enemy_hp[i] <= 0) // 敌机被击毁
                {
                    boom_x = enemy_x[i] + enemy_w / 2 - boom_w / 2;
                    boom_y = enemy_y[i] + enemy_h / 2 - boom_h / 2;
                    score++; // 增加得分
                }
            }
        }
    }
    for(int i = 0; i < ENEMY_NUM; i++) // 英雄飞机和敌机的碰撞检测
    {
        if(enemy_hp[i] > 0 &&
           hero_x + hero_w > enemy_x[i] &&
           hero_x < enemy_x[i] + enemy_w &&
           hero_y + hero_h > enemy_y[i] &&
           hero_y < enemy_y[i] + enemy_h)
        {
            enemy_hp[i] = 0; // 减少敌机生命值
            hp--; // 减少生命值
            boom_x = hero_x + hero_w / 2 - boom_w / 2;
            boom_y = hero_y + hero_h / 2 - boom_h / 2;
            if(hp > 0) // 英雄飞机重新出现
            {
                hero_x = (WIDTH - hero_w) / 2;
                hero_y = HEIGHT - hero_h - 50;
            }
        }
    }
}

游戏结束处理函数：

void game_over()
{
    is_game_over = true;
    putimage(boom_x, boom_y, &boom); // 绘制爆炸效果
    settextcolor(WHITE);
    outtextxy(WIDTH / 2 - 50, HEIGHT / 2, "Game Over"); // 绘制游戏结束文字
}

到这里，一个简单的飞机大战小游戏就完成了。完整代码如下：