save project

snake.py

@@ -24,7 +24,7 @@ apple_y=300
 
 setheading = "right"
 snake_head = right
-
+screen=0
 while True:
     for event in pygame.event.get():
         if event.type == locals.QUIT:
@@ -61,6 +61,8 @@ while True:
         apple_y=30*num2-30
     else:
         position.pop(0)
+    if x <0 or x > 630 or y < 0 or y > 450:
+        exit()
     # 将背景图画上去
     screen.blit(background, (0, 0))
     # 将贪吃蛇的头画上去