Answers

10.5 A team in a game

Competing · Robot club · about 14 min

What this lesson is about

Radio in a game, agreeing roles without talking, and swapping jobs when the score says so.

• Saying who does what
• A rule that settles it without talking
• Swapping jobs

Questions 6 marks in all

1. [1 mark]In a game, who hears your send("striker")?

   1. AEvery robot on the mat, including the other team
   2. BOnly your team mates
   3. COnly robots within 50 cm
   4. DOnly the game's scorer
   Answer: A. Say what your team needs and nothing you would mind an opponent knowing.

2. [1 mark]What does this program print?

   team = ["bot-7", "bot-2"]
   for me in team:
       job = "attack" if me == min(team) else "defend"
       print(me, job)

   Answer:

   bot-7 defend
   bot-2 attack

   min of a list of names picks the one that sorts first, bot-2. Both robots run the same rule and agree without a word.

3. [1 mark]What does this program print?

   team = ["bot-10", "bot-9"]
   print(min(team))

   Answer:

   bot-10

   Names sort as text, character by character, and 1 comes before 9. So bot-10 sorts first, which is fine as long as both robots use the same rule.

4. [1 mark]Why is a rule like the name that sorts first attacks often better than agreeing by radio?

   1. AIt cannot be jammed, cannot arrive late, and works on the first tick
   2. BIt lets you change jobs more often
   3. CThe other team cannot read your name
   4. DRadio does not work in games
   Answer: A. Radio is useful, but a shared rule needs no message at all.

5. [1 mark]Your attacker has been taken out. What should the defender do?

   1. ABecome the attacker
   2. BKeep defending, since jobs are fixed
   3. CStop and wait for the attacker to return
   4. DSend the score to the other team
   Answer: A. Fixed jobs lose to a team that notices. Swap when it makes sense.

6. [1 mark]In the task, a robot sends attack and then drives to the near base. What is wrong?

   1. AWhat it said and what it did do not match: attack means the far base
   2. BNothing, the message is what counts
   3. CIt should not send anything
   4. Dattack should be in capitals
   Answer: A. Send attack and go to the far base, or send defend and go to the near one. A team mate relies on both matching.

The task: call it and go

from bugbot import *
connect()

# say what you are doing, then do it
send("attack")

from bugbot import *
connect()
send('attack')
while position()[1] < 38:
    forward(50)
    wait(0.1)
while position()[0] > -22:
    left(50)
    wait(0.1)
stop()