“海龟车的程序解释”版本间的差异

2016年4月6日 (三) 03:03的最后版本

原有的程序

globals [ sample-car ] turtles-own [ speed speed-limit speed-min ]

to setup

 clear-all
 ask patches [ setup-road ]
 setup-cars
 watch sample-car
 reset-ticks

end

to setup-road ;; patch procedure

 if (pycor < 2) and (pycor > -2) [ set pcolor white ]

end

to setup-cars

 if number-of-cars > world-width [
   user-message (word
     "There are too many cars for the amount of road.  Please decrease the NUMBER-OF-CARS slider to below "
     (world-width + 1) " and press the SETUP button again.  The setup has stopped.")
   stop
 ]
 set-default-shape turtles "car"
 create-turtles number-of-cars [
   set color blue
   set xcor random-xcor
   set heading 90
   ;; set initial speed to be in range 0.1 to 1.0
   set speed 0.1 + random-float 0.9
   set speed-limit 1
   set speed-min 0
   separate-cars
 ]
 set sample-car one-of turtles
 ask sample-car [ set color red ]

end

this procedure is needed so when we click "Setup" we

don't end up with any two cars on the same patch

to separate-cars ;; turtle procedure

 if any? other turtles-here [
   fd 1
   separate-cars
 ]

end

to go

 ;; if there is a car right ahead of you, match its speed then slow down
 ask turtles [
   let car-ahead one-of turtles-on patch-ahead 1
   ifelse car-ahead != nobody
     [ slow-down-car car-ahead ]
     [ speed-up-car ] ;; otherwise, speed up
   ;; don't slow down below speed minimum or speed up beyond speed limit
   if speed < speed-min [ set speed speed-min ]
   if speed > speed-limit [ set speed speed-limit ]
   fd speed
 ]
 tick

end

turtle (car) procedure

to slow-down-car [ car-ahead ]

 ;; slow down so you are driving more slowly than the car ahead of you
 set speed [ speed ] of car-ahead - deceleration

end

turtle (car) procedure

to speed-up-car

 set speed speed + acceleration

end

Copyright 1997 Uri Wilensky.

See Info tab for full copyright and license.

定义全局变量 sample-car

定义属于海龟的变量 speed speed-limit speed-min

对于setup

将全局变量清0

要求patchs执行setup-road

setup-cars

观察 sample-car

将时钟计数器重设为0

结束

对于setup-road

在y坐标位于（-2,2）内的瓦片，设置颜色为白色

结束

对于setup-cars

如果汽车数量大于世界宽度

则执行“ 弹出用户信息，文字：There are too many cars for the amount of road. Please decrease the NUMBER-OF-CARS slider to below "(world-width

+ 1) " and press the SETUP button again. The setup has stopped

结束”

设置海龟的默认初始图形为 车

设置海龟数量“设置颜色 蓝色

设置海龟随机位置

设置海龟面向东

设置速度 speed 为0.1+0~0.9之间的随机浮点数

设置速度上限speed limit 1，下限speed min 0

seperate-cars”

设置sample car为海龟集合的随机一个

请求sample car设置颜色为红色

结束

对于seperate-cars

如果这里有了其他海龟车，那么“前进一步，separate-cars”

结束

对于go

请求海龟“让 car-ahead 是随机海龟前方一格瓦片上的海龟

如果 car-ahead 得到的不是nobody，那么减速（slow-down-car car-ahead)，否则加速(speed-up-car)

如果速度小于最小速度，那么让最小速度取代速度

如果速度大于最大速度，那么让最大速度取代速度

让海龟前进速度的步数”

时钟计数器前进1

结束

对于slow-down-car car-ahead

设置 速度speed 为 car-ahead的speed减去deceleration

对于speed-up-car

设置速度speed 为 speed加上acceleration