编一个贪吃蛇代码

好的，以下是一个简单的贪吃蛇代码实现，使用 Python 语言:

import pygame
import random

# 定义常量
WIDTH = 640
HEIGHT = 480
CELL_SIZE = 20
SPEED = 10

# 颜色
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
RED = (255, 0, 0)
GREEN = (0, 255, 0)

# 初始化 Pygame
pygame.init()

# 设置窗口
window = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption('贪吃蛇')

# 定义蛇类
class Snake:
    def __init__(self):
        self.body = [(4, 3), (3, 3), (2, 3)]
        self.direction = 'right'

    def move(self):
        head = self.body[0]
        if self.direction == 'up':
            new_head = (head[0], head[1] - 1)
        elif self.direction == 'down':
            new_head = (head[0], head[1] + 1)
        elif self.direction == 'left':
            new_head = (head[0] - 1, head[1])
        elif self.direction == 'right':
            new_head = (head[0] + 1, head[1])
        self.body.insert(0, new_head)
        self.body.pop()

    def grow(self):
        tail = self.body[-1]
        self.body.append(tail)

    def is_collide(self):
        head = self.body[0]
        if head[0] < 0 or head[0] >= WIDTH / CELL_SIZE:
            return True
        if head[1] < 0 or head[1] >= HEIGHT / CELL_SIZE:
            return True
        for i in range(1, len(self.body)):
            if head == self.body[i]:
                return True
        return False

    def draw(self):
        for cell in self.body:
            rect = pygame.Rect(cell[0]*CELL_SIZE, cell[1]*CELL_SIZE, CELL_SIZE, CELL_SIZE)
            pygame.draw.rect(window, GREEN, rect)

# 定义食物类
class Food:
    def __init__(self):
        self.position = (random.randint(0, WIDTH/CELL_SIZE-1), random.randint(0, HEIGHT/CELL_SIZE-1))

    def draw(self):
        rect = pygame.Rect(self.position[0]*CELL_SIZE, self.position[1]*CELL_SIZE, CELL_SIZE, CELL_SIZE)
        pygame.draw.rect(window, RED, rect)

# 创建蛇和食物
snake = Snake()
food = Food()

# 游戏循环
clock = pygame.time.Clock()
running = True
while running:
    # 处理事件
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYDOWN:
            if event.key == pygame.K_UP and snake.direction != 'down':
                snake.direction = 'up'
            elif event.key == pygame.K_DOWN and snake.direction != 'up':
                snake.direction = 'down'
            elif event.key == pygame.K_LEFT and snake.direction != 'right':
                snake.direction = 'left'
            elif event.key == pygame.K_RIGHT and snake.direction != 'left':
                snake.direction = 'right'

    # 移动蛇和检测碰撞
    snake.move()
    if snake.is_collide():
        running = False

    # 检测是否吃到食物
    if snake.body[0] == food.position:
        snake.grow()
        food = Food()

    # 绘制场景
    window.fill(BLACK)
    snake.draw()
    food.draw()
    pygame.display.update()

    # 控制帧率
    clock.tick(SPEED)

# 退出 Pygame
pygame.quit()
exit()

注意，这只是一个简单的实现，还有很多细节可以完善，比如增加蛇的长度、速度随着时间增加、死亡动画等。