auto save

snake.py

 import pygame
 from pygame import locals
-from random
+import random
 # 初始化pygame，为使用硬件做准备
 pygame.init()
 
@@ -54,8 +54,9 @@ while True:
         y += 30
     position.append((x, y))
     if x==a_x and y==a_y:
-        a_x=random.randint(0,680)
-        a_y=random.randint(0,480)
+        a_x=30*random.randint(1,21)
+        a_y=30*random.randint(1,15)
+    else:
         position.pop(0)
     # 将背景图画上去
     screen.blit(background, (0, 0))