用qt程序构建一个贪吃蛇游戏的代码

以下是使用Qt编写的贪吃蛇游戏代码示例：

#include <QMainWindow>
#include <QPainter>
#include <QKeyEvent>
#include <QTimer>

class SnakeGame : public QMainWindow {
  Q_OBJECT

 public:
  SnakeGame(QWidget *parent = nullptr) : QMainWindow(parent) {
    setFixedSize(400, 400);
    snake_.push_back({200, 200});
    snake_.push_back({200, 210});
    snake_.push_back({200, 220});
    food_ = generateFood();
    QTimer *timer = new QTimer(this);
    connect(timer, SIGNAL(timeout()), this, SLOT(update()));
    timer->start(100);
  }

 protected:
  void paintEvent(QPaintEvent *event) override {
    QPainter painter(this);
    painter.setPen(Qt::NoPen);
    painter.setBrush(Qt::black);
    painter.drawRect(0, 0, width(), height());
    painter.setBrush(Qt::red);
    painter.drawRect(food_.x(), food_.y(), 10, 10);
    painter.setBrush(Qt::green);
    for (const auto &pos : snake_) {
      painter.drawRect(pos.x(), pos.y(), 10, 10);
    }
  }

  void keyPressEvent(QKeyEvent *event) override {
    if (event->key() == Qt::Key_Left && direction_ != Direction::Right) {
      direction_ = Direction::Left;
    } else if (event->key() == Qt::Key_Right && direction_ != Direction::Left) {
      direction_ = Direction::Right;
    } else if (event->key() == Qt::Key_Up && direction_ != Direction::Down) {
      direction_ = Direction::Up;
    } else if (event->key() == Qt::Key_Down && direction_ != Direction::Up) {
      direction_ = Direction::Down;
    }
  }

 private slots:
  void update() {
    QPoint head = snake_.front();
    switch (direction_) {
      case Direction::Left:
        head.rx() -= 10;
        break;
      case Direction::Right:
        head.rx() += 10;
        break;
      case Direction::Up:
        head.ry() -= 10;
        break;
      case Direction::Down:
        head.ry() += 10;
        break;
    }
    if (head == food_) {
      snake_.push_front(head);
      food_ = generateFood();
    } else {
      snake_.pop_back();
      if (std::find(snake_.begin(), snake_.end(), head) != snake_.end() ||
          head.x() < 0 || head.x() > width() || head.y() < 0 || head.y() > height()) {
        snake_.clear();
        snake_.push_back({200, 200});
        snake_.push_back({200, 210});
        snake_.push_back({200, 220});
        food_ = generateFood();
      } else {
        snake_.push_front(head);
      }
    }
    update();
  }

 private:
  enum class Direction { Left, Right, Up, Down };
  QList<QPoint> snake_;
  QPoint food_;
  Direction direction_ = Direction::Up;

  QPoint generateFood() {
    int x = (qrand() % (width() / 10)) * 10;
    int y = (qrand() % (height() / 10)) * 10;
    return {x, y};
  }
};

此代码使用Qt绘制了一个400x400像素的窗口，并在其中创建了一个贪吃蛇游戏。运行程序后，玩家可以通过方向键控制蛇的移动，吃到食物后蛇的长度会增加。如果蛇碰到了边界或自己的身体，则游戏会重新开始。