save project

snake.py

@@ -62,6 +62,8 @@ while True:
         score=score+10
         score=score+10
     else:      
     else:      
         position.pop(0)
         position.pop(0)
+    if x <0 or x >630 or y < 0 or y > 450:
+        exit(    
     # 将背景图画上去
     # 将背景图画上去
     screen.blit(background, (0, 0))
     screen.blit(background, (0, 0))
     # 将贪吃蛇的头画上去
     # 将贪吃蛇的头画上去