Quiz Engine III

Review — Quiz Engine II 5 min

• Random picks repeat. Deleting as you go empties the bank.
• Fisher-Yates swapped each place, from the bottom up, with one at or above it.
• A swap needed temp. Without it, one number was copied and another lost.
• The answers were shuffled too, and item # of found the right one.

Quick-fire

Kart Racer’s Gate counted next gate up to 4, then back to 1. Which block did that?

Today’s Topic 3 min

• Two lists in step: players and scores
• A turn that wraps: (((turn) mod (length of [players v])) + (1))
• A pass-it-on card, and a timer for each question
• A winner, and a tie when two players share the best score

Learning outcome

By the end of this lesson you will be able to:

1. Keep one number per player in a list and change the right one.
2. Take turns round any number of players.
3. Find the best score and every player who has it.

Learnt — a quiz for the whole room 28 min

1 · Whose turn?

The names go in a list called players. turn is a row number: (item (turn) of [players v]) is whoever is playing. After each turn it moves on by one — and after the last player, it wraps back to 1.

set [turn v] to (1)
repeat (10)
  say (join (item (turn) of [players v]) ['s turn]) for (0.6) seconds
  set [turn v] to (((turn) mod (length of [players v])) + (1))
end
            

2 · Scores in step, and passing the laptop

A second list, scores, has one row per player. Row turn of it is the score of whoever is playing, so a point goes there:

replace item (turn) of [scores v] with ((item (turn) of [scores v]) + (1))
            

Before each question, a Pass card says it is time to hand the laptop on. The question waits until the next player presses space.

broadcast (pass v) and wait
say (join (item (turn) of [players v]) [, press space when you have the laptop.])
wait until <key (space v) pressed?>
            

3 · A timer for each question

Write down the timer when the question appears. When the answer comes back, take it away. Too slow scores nothing.

set [asked at v] to (timer)
ask (question) and wait
set [took v] to (([round v] of (((timer) - (asked at)) * (10))) / (10))
if <(took) > (5)> then
  say (join [Too slow! ] (join (took) [ s])) for (0.6) seconds
else
  // check the answer, as before
end
            

4 · The winner — or a tie

Two passes through the scores. The first finds the best score. The second collects every player who has it into a winners list.

set [best v] to (item (1) of [scores v])
set [k v] to (1)
repeat (length of [scores v])
  if <(item (k) of [scores v]) > (best)> then
    set [best v] to (item (k) of [scores v])
  end
  change [k v] by (1)
end
delete all of [winners v]
set [k v] to (1)
repeat (length of [scores v])
  if <(item (k) of [scores v]) = (best)> then
    add (item (k) of [players v]) to [winners v]
  end
  change [k v] by (1)
end
            

Basic — a three-player quiz 25 min

Open your quiz from Quiz Engine II. You can keep the shuffles in.

Step 1 — the players

1. Make two lists, players and scores, and type three names into players.
2. Make a winners list and the variables turn, best and k.
3. Under the green flag: delete all of [scores v], then repeat (length of [players v]) with add (0) to [scores v] inside.

Step 2 — the Pass card

1. Save our card, pass-card.svg, and use Upload Sprite. Call it Pass card.
2. Give it the receive script from Learnt section 2.

Step 3 — turns

1. In the quiz loop, before the split: the three pass blocks from section 2.
2. A right answer replaces the player’s row in scores, instead of changing score.
3. At the end of the loop, move the turn on with mod.
4. After the loop, find the winners, then say the winner or the tie.

A score line

Everybody wants to know the scores.

• After every turn, Kiran says every player’s name and score in one line.
• The line is built by a loop, so it works for 2, 3 or 4 players.
• A dot goes between players, but not after the last one.

set [line v] to []
set [k v] to (1)
repeat (length of [players v])
  set [line v] to (join (line) (join (item (k) of [players v]) (join [ ] (item (k) of [scores v]))))
  if <(k) < (length of [players v])> then
    set [line v] to (join (line) [ · ])
  end
  change [k v] by (1)
end
say (line) for (0.9) seconds
            

Rounds

Fair games give everyone the same number of questions.

• A rounds variable: how many questions each player gets.
• The game plays exactly rounds × players turns, then ends itself.
• Then it names the winner.

A speed bonus

Reward the quick thinkers.

• A right answer in under 2 seconds scores 2.
• A right answer that is slower scores 1.
• A wrong answer scores 0, however fast.

if <(item ((pick) + (1)) of [parts v]) = (item (5) of [parts v])> then
  if <(took) < (2)> then
    replace item (turn) of [scores v] with ((item (turn) of [scores v]) + (2))
  else
    replace item (turn) of [scores v] with ((item (turn) of [scores v]) + (1))
  end
end
            

Sudden death

A tie is fair, but a room full of players usually wants a winner.

• If two players tie, they get one extra question each.
• If one is right and the other is not, the right one wins.
• If they are both right or both wrong, go again.

Summary 5 min

• players and scores are two lists in step. turn is the row playing.
• ((turn) mod (players)) + 1 goes round any number of players.
• A question timer is the timer now, take away the timer when it was asked.
• Find the best score first, then every player with it. More than one is a tie.

Turn

Whose go it is — here, a row number in the players list.

Mod

The remainder after dividing. It makes a count go round in a circle.

Tie

Two or more players sharing the best score.

Hand in

Save your pass-and-play quiz. Next lesson it remembers the best players even after the game is over, and loads whole question packs from a single code.