Rock-paper-scissors: Difference between revisions

=={{header|Nim}}==

<lang Nim>import random, strutils, tables

type

Choice {.pure.} = enum Rock, Paper, Scissors

History = tuple[total: int; counts: CountTable[Choice]]

const Successors: array[Choice, Choice] = [Paper, Scissors, Rock]

func `>`(a, b: Choice): bool =

## By construction, only the successor is greater than the choice.

a == Successors[b]

proc choose(history: History): Choice =

## Make a weighted random choice using the player counts

## then select the choice likely to beat it.

var value = rand(1..history.total)

for choice, count in history.counts.pairs:

if value <= count:

return Successors[choice]

dec value, count

randomize()

# Initialize history with one for each choice in order to avoid special case.

var history: History = (3, [Rock, Paper, Scissors].toCountTable)

echo "To quit game, type 'q' when asked for your choice."

var myChoice, yourChoice: Choice

var myWins, yourWins = 0

while true:

# Get player choice.

try:

stdout.write "Rock(1), paper(2), scissors(3). Your choice? "

let answer = stdin.readLine().strip()

if answer == "q":

quit "Quitting game.", QuitSuccess

if answer notin ["1", "2", "3"]:

echo "Invalid choice."

continue

yourChoice = Choice(ord(answer[0]) - ord('1'))

except EOFError:

quit "Quitting game.", QuitFailure

# Make my choice.

myChoice = history.choose()

echo "I choosed ", myChoice, '.'

history.counts.inc yourChoice

inc history.total

# Display result of round.

if myChoice == yourChoice:

echo "It’s a tie."

elif myChoice > yourChoice:

echo "I win."

inc myWins

else:

echo "You win."

inc yourWins

echo "Total wins. You: ", yourWins, " Me: ", myWins</lang>

{{out}}

<pre>To quit game, type 'q' when asked for your choice.

Rock(1), paper(2), scissors(3). Your choice? 1

I choosed Rock.

It’s a tie.

Total wins. You: 0 Me: 0

Rock(1), paper(2), scissors(3). Your choice? 1

I choosed Rock.

It’s a tie.

Total wins. You: 0 Me: 0

Rock(1), paper(2), scissors(3). Your choice? 1

I choosed Paper.

I win.

Total wins. You: 0 Me: 1

Rock(1), paper(2), scissors(3). Your choice? 1

I choosed Rock.

It’s a tie.

Total wins. You: 0 Me: 1

Rock(1), paper(2), scissors(3). Your choice? 1

I choosed Paper.

I win.

Total wins. You: 0 Me: 2

Rock(1), paper(2), scissors(3). Your choice? 1

I choosed Paper.

I win.

Total wins. You: 0 Me: 3

Rock(1), paper(2), scissors(3). Your choice? 1

I choosed Paper.

I win.

Total wins. You: 0 Me: 4

Rock(1), paper(2), scissors(3). Your choice? 1

I choosed Paper.

I win.

Total wins. You: 0 Me: 5

Rock(1), paper(2), scissors(3). Your choice? 1

I choosed Paper.

I win.

Total wins. You: 0 Me: 6

Rock(1), paper(2), scissors(3). Your choice? q

Quitting game.</pre>