Rock-paper-scissors: Difference between revisions
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=={{header|BASIC}}== |
=={{header|BASIC}}== |
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{{works with|QBasic}} |
{{works with|QBasic}} |
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Note that this was tested in [[FreeBASIC]] using the <code>-lang qb</code> switch, not actually in QBasic. |
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<lang qbasic>DIM pPLchoice(1 TO 3) AS INTEGER, pCMchoice(1 TO 3) AS INTEGER |
<lang qbasic>DIM pPLchoice(1 TO 3) AS INTEGER, pCMchoice(1 TO 3) AS INTEGER |
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Revision as of 03:22, 28 October 2011
You are encouraged to solve this task according to the task description, using any language you may know.
The task is to implement the classic children's game Rock-paper-scissors, as well as a simple predictive AI player.
Rock Paper Scissors is a two player game. Each player chooses one of rock, paper or scissors, without knowing the other player's choice. The winner is decided by a set of rules:
- Rock beats scissors
- Scissors beat paper
- Paper beats rock.
If both players choose the same thing, there is no winner for that round.
For this task, the computer will be one of the players. The operator will select Rock, Paper or Scissors and the computer will keep a record of the choice frequency, and use that information to make a weighted random choice in an attempt to defeat its opponent.
Ada
<lang Ada>with Ada.Text_IO; with Ada.Numerics.Float_Random;
procedure Rock_Paper_Scissors is
package Rand renames Ada.Numerics.Float_Random; Gen: Rand.Generator;
type Choice is (Rock, Paper, Scissors);
Cnt: array (Choice) of Natural := (1, 1, 1);
-- for the initialization: pretend that each of Rock, Paper,
-- and Scissors, has been played once by the human
-- else the first computer choice would be deterministic
function Computer_Choice return Choice is
Random_Number: Natural :=
Integer(Rand.Random(Gen)
* (Float(Cnt(Rock)) + Float(Cnt(Paper)) + Float(Cnt(Scissors))));
begin
if Random_Number < Cnt(Rock) then
-- guess the human will choose Rock
return Paper;
elsif Random_Number - Cnt(Rock) < Cnt(Paper) then
-- guess the human will choose Paper
return Scissors;
else -- guess the human will choose Scissors
return Rock;
end if;
end Computer_Choice;
Finish_The_Game: exception;
function Human_Choice return Choice is
Done: Boolean := False;
T: constant String
:= "enter ""r"" for Rock, ""p"" for Paper, or ""s"" for Scissors""!";
U: constant String
:= "or enter ""q"" to Quit the game";
Result: Choice;
begin
Ada.Text_IO.Put_Line(T);
Ada.Text_IO.Put_Line(U);
while not Done loop
Done := True;
declare
S: String := Ada.Text_IO.Get_Line;
begin
if S="r" or S="R" then
Result := Rock;
elsif S="p" or S = "P" then
Result := Paper;
elsif S="s" or S="S" then
Result := Scissors;
elsif S="q" or S="Q" then
raise Finish_The_Game;
else
Done := False;
end if;
end;
end loop;
return Result;
end Human_Choice;
type Result is (Human_Wins, Draw, Computer_Wins);
function "<" (X, Y: Choice) return Boolean is
-- X < Y if X looses against Y
begin
case X is
when Rock => return (Y = Paper);
when Paper => return (Y = Scissors);
when Scissors => return (Y = Rock);
end case;
end "<";
Score: array(Result) of Natural := (0, 0, 0);
C,H: Choice;
Res: Result;
begin
-- play the game
loop
C := Computer_Choice; -- the computer makes its choice first
H := Human_Choice; -- now ask the player for his/her choice
Cnt(H) := Cnt(H) + 1; -- update the counts for the AI
if C < H then
Res := Human_Wins;
elsif H < C then
Res := Computer_Wins;
else
Res := Draw;
end if;
Ada.Text_IO.Put_Line("COMPUTER'S CHOICE: " & Choice'Image(C)
& " RESULT: " & Result'Image(Res));
Ada.Text_IO.New_Line;
Score(Res) := Score(Res) + 1;
end loop;
exception
when Finish_The_Game =>
Ada.Text_IO.New_Line;
for R in Score'Range loop
Ada.Text_IO.Put_Line(Result'Image(R) & Natural'Image(Score(R)));
end loop;
end Rock_Paper_Scissors;</lang>
First and last few lines of the output of a game, where the human did permanently choose Rock:
./rock_paper_scissors enter "r" for Rock, "p" for Paper, or "s" for Scissors"! or enter "q" to Quit the game r COMPUTER'S CHOICE: SCISSORS RESULT: HUMAN_WINS enter "r" for Rock, "p" for Paper, or "s" for Scissors"! or enter "q" to Quit the game r COMPUTER'S CHOICE: ROCK RESULT: DRAW enter "r" for Rock, "p" for Paper, or "s" for Scissors"! or enter "q" to Quit the game r COMPUTER'S CHOICE: SCISSORS RESULT: HUMAN_WINS enter "r" for Rock, "p" for Paper, or "s" for Scissors"! or enter "q" to Quit the game r COMPUTER'S CHOICE: ROCK RESULT: DRAW [...] enter "r" for Rock, "p" for Paper, or "s" for Scissors"! or enter "q" to Quit the game r COMPUTER'S CHOICE: ROCK RESULT: DRAW enter "r" for Rock, "p" for Paper, or "s" for Scissors"! or enter "q" to Quit the game r COMPUTER'S CHOICE: PAPER RESULT: COMPUTER_WINS enter "r" for Rock, "p" for Paper, or "s" for Scissors"! or enter "q" to Quit the game q HUMAN_WINS 2 DRAW 5 COMPUTER_WINS 21
BASIC
<lang qbasic>DIM pPLchoice(1 TO 3) AS INTEGER, pCMchoice(1 TO 3) AS INTEGER DIM choices(1 TO 3) AS STRING DIM playerwins(1 TO 3) AS INTEGER DIM playerchoice AS INTEGER, compchoice AS INTEGER DIM playerwon AS INTEGER, compwon AS INTEGER, tie AS INTEGER DIM tmp AS INTEGER
' Do it this way for QBasic; FreeBASIC supports direct array assignment. DATA "rock", "paper", "scissors" FOR tmp = 1 to 3
READ choices(tmp)
NEXT DATA 3, 1, 2 FOR tmp = 1 to 3
READ playerwins(tmp)
NEXT
RANDOMIZE TIMER
DO
' Computer chooses first to ensure there's no "cheating".
compchoice = INT(RND * (pPLchoice(1) + pPLchoice(2) + pPLchoice(3) + 3))
SELECT CASE compchoice
CASE 0 to (pPLchoice(1))
' Player past choice: rock; choose paper.
compchoice = 2
CASE (pPLchoice(1) + 1) TO (pPLchoice(1) + pPLchoice(2) + 1)
' Player past choice: paper; choose scissors.
compchoice = 3
CASE (pPLchoice(1) + pPLchoice(2) + 2) TO (pPLchoice(1) + pPLchoice(2) + pPLchoice(3) + 2)
' Player past choice: scissors; choose rock.
compchoice = 1
END SELECT
PRINT "Rock, paper, or scissors ";
DO
PRINT "[1 = rock, 2 = paper, 3 = scissors, 0 to quit]";
INPUT playerchoice
LOOP WHILE (playerchoice < 0) OR (playerchoice > 3)
IF 0 = playerchoice THEN EXIT DO
pCMchoice(compchoice) = pCMchoice(compchoice) + 1
pPLchoice(playerchoice) = pPLchoice(playerchoice) + 1
PRINT "You chose "; choices(playerchoice); " and I chose "; choices(compchoice); ". ";
IF (playerchoice) = compchoice THEN
PRINT "Tie!"
tie = tie + 1
ELSEIF (compchoice) = playerwins(playerchoice) THEN
PRINT "You won!"
playerwon = playerwon + 1
ELSE
PRINT "I won!"
compwon = compwon + 1
END IF
LOOP
PRINT "Some useless statistics:" PRINT "You won "; STR$(playerwon); " times, and I won "; STR$(compwon); " times; "; STR$(tie); " ties." PRINT , choices(1), choices(2), choices(3) PRINT "You chose:", pPLchoice(1), pPLchoice(2), pPLchoice(3) PRINT " I chose:", pCMchoice(1), pCMchoice(2), pCMchoice(3)</lang>
A sample game:
$ ./rokpprscr
Rock, paper, or scissors [1 = rock, 2 = paper, 3 = scissors, 0 to quit]? 1
You chose rock and I chose paper. I won!
Rock, paper, or scissors [1 = rock, 2 = paper, 3 = scissors, 0 to quit]? 1
You chose rock and I chose scissors. You won!
[... 56 more times choosing "rock"...]
Rock, paper, or scissors [1 = rock, 2 = paper, 3 = scissors, 0 to quit]? 1
You chose rock and I chose paper. I won!
Rock, paper, or scissors [1 = rock, 2 = paper, 3 = scissors, 0 to quit]? 1
You chose rock and I chose paper. I won!
Rock, paper, or scissors [1 = rock, 2 = paper, 3 = scissors, 0 to quit]? 3
You chose scissors and I chose paper. You won!
Rock, paper, or scissors [1 = rock, 2 = paper, 3 = scissors, 0 to quit]?
Some useless statistics:
You won 5 times, and I won 54 times; 2 ties.
rock paper scissors
You chose: 60 0 1
I chose: 2 55 4
This works with a tiny, integer BASIC interpreter. The expression:
CHOOSE X=3
Is equivalent to:
LET X=INT(RND(1)*3)
This implementation uses a 6-bits binary scheme, where the lower three bits represent the choice of the user and the higher three bits the choice of the computer:
<lang ubasic> 20 LET P=0: LET Q=0: LET Z=0
30 INPUT "Rock, paper, or scissors (1 = rock, 2 = paper, 3 = scissors)? ", A 40 IF A>3 THEN GOTO 400 50 IF A=3 THEN LET A=4 60 IF A<1 THEN GOTO 400 70 CHOOSE C=3 : LET D=4: FOR B=1 TO C+1 : LET D = D+D : NEXT : GOTO (A+D)*10 90 Z=Z+1 : PRINT "We both chose 'rock'. It's a draw." : GOTO 30
100 P=P+1 : PRINT "You chose 'paper', I chose 'rock'. You win.." : GOTO 30 120 Q=Q+1 : PRINT "You chose 'scissors', I chose 'rock'. I win!" : GOTO 30 170 Q=Q+1 : PRINT "You chose 'rock', I chose 'paper'. I win!" : GOTO 30 180 Z=Z+1 : PRINT "We both chose 'paper'. It's a draw." : GOTO 30 200 P=P+1 : PRINT "You chose 'scissors', I chose 'paper'. You win.." : GOTO 30 330 P=P+1 : PRINT "You chose 'rock', I chose 'scissors'. You win.." : GOTO 30 340 Q=Q+1 : PRINT "You chose 'paper', I chose 'scissors'. I win!" : GOTO 30 360 Z=Z+1 : PRINT "We both chose 'scissors'. It's a draw." : GOTO 30 400 PRINT "There were ";Z;" draws. I lost ";P;" times, you lost ";Q;" times." : END</lang>
A sample game:
Rock, paper, or scissors (1 = rock, 2 = paper, 3 = scissors)? 1 You chose 'rock', I chose 'paper'. I win! Rock, paper, or scissors (1 = rock, 2 = paper, 3 = scissors)? 2 You chose 'paper', I chose 'scissors'. I win! Rock, paper, or scissors (1 = rock, 2 = paper, 3 = scissors)? 3 You chose 'scissors', I chose 'paper'. You win.. Rock, paper, or scissors (1 = rock, 2 = paper, 3 = scissors)? 1 You chose 'rock', I chose 'paper'. I win! Rock, paper, or scissors (1 = rock, 2 = paper, 3 = scissors)? 2 We both chose 'paper'. It's a draw. Rock, paper, or scissors (1 = rock, 2 = paper, 3 = scissors)? 3 You chose 'scissors', I chose 'rock'. I win! Rock, paper, or scissors (1 = rock, 2 = paper, 3 = scissors)? 4 There were 1 draws. I lost 1 times, you lost 4 times.
BBC BASIC
<lang bbcbasic>PRINT"Welcome to the game of rock-paper-scissors" PRINT "Each player guesses one of these three, and reveals it at the same time." PRINT "Rock blunts scissors, which cut paper, which wraps stone." PRINT "If both players choose the same, it is a draw!" PRINT "When you've had enough, choose Q." DIM rps%(2),g$(3) g$()="rock","paper","scissors" total%=0 draw%=0 pwin%=0 cwin%=0 c%=RND(3) PRINT"What is your move (press R, P, or S)?" REPEAT
REPEAT q$=GET$ UNTIL INSTR("RPSrpsQq",q$)>0
g%=(INSTR("RrPpSsQq",q$)-1) DIV 2
IF g%>2 THEN PROCsummarise:END
total%+=1
rps%(g%)+=1
PRINT"You chose ";g$(g%);" and I chose ";g$(c%);
CASE g%-c% OF
WHEN 0:
PRINT ". It's a draw"
draw%+=1
WHEN 1,-2:
PRINT ". You win!"
pwin%+=1
WHEN -1,2:
PRINT ". I win!"
cwin%+=1
ENDCASE
c%=FNmove(rps%(),total%)
UNTIL FALSE END
DEFPROCsummarise PRINT "You won ";pwin%;", and I won ";cwin%;". There were ";draw%;" draws" PRINT "Thanks for playing!" ENDPROC
DEFFNmove(p%(),t%) LOCAL r% r%=RND(total%) IF r%<=p%(0) THEN =1 IF r%<=p%(0)+p%(1) THEN =2 =0</lang>
Sample output:
Welcome to the game of rock-paper-scissors Each player guesses one of these three, and reveals it at the same time. Rock blunts scissors, which cut paper, which wraps stone. If both players choose the same, it is a draw! When you've had enough, choose Q. What is your move (press R, P, or S)? You chose rock and I chose paper. I win! You chose scissors and I chose paper. You win! You chose scissors and I chose paper. You win! You chose scissors and I chose paper. You win! You chose scissors and I chose paper. You win! You chose scissors and I chose rock. I win! You chose paper and I chose paper. It's a draw You chose paper and I chose rock. You win! You chose paper and I chose rock. You win! You chose paper and I chose paper. It's a draw You chose paper and I chose paper. It's a draw You chose paper and I chose rock. You win! You chose scissors and I chose rock. I win! You chose scissors and I chose scissors. It's a draw You chose scissors and I chose rock. I win! You chose scissors and I chose scissors. It's a draw You chose scissors and I chose rock. I win! You won 7, and I won 5. There were 5 draws Thanks for playing!
C
<lang C>#include <stdio.h>
- include <stdlib.h>
int rand_i(int n) { int rand_max = RAND_MAX - (RAND_MAX % n); int ret; while ((ret = rand()) >= rand_max); return ret/(rand_max / n); }
int weighed_rand(int *tbl, int len) { int i, sum, r; for (i = 0, sum = 0; i < len; sum += tbl[i++]); if (!sum) return rand_i(len);
r = rand_i(sum) + 1; for (i = 0; i < len && (r -= tbl[i]) > 0; i++); return i; }
int main() { int user_action, my_action; int user_rec[] = {0, 0, 0}; char *names[] = { "Rock", "Paper", "Scissors" }; char str[2]; char *winner[] = { "We tied.", "Meself winned.", "You win." };
while (1) { my_action = (weighed_rand(user_rec, 3) + 1) % 3;
printf("\nYour choice [1-3]:\n" " 1. Rock\n 2. Paper\n 3. Scissors\n> ");
/* scanf is a terrible way to do input. should use stty and keystrokes */ if (!scanf("%d", &user_action)) { scanf("%1s", str); if (*str == 'q') return 0; continue; } user_action --; if (user_action > 2 || user_action < 0) { printf("invalid choice; again\n"); continue; } printf("You chose %s; I chose %s. %s\n", names[user_action], names[my_action], winner[(my_action - user_action + 3) % 3]);
user_rec[user_action]++; } }</lang>
Euphoria
<lang euphoria>function weighted_rand(sequence table)
integer sum,r
sum = 0
for i = 1 to length(table) do
sum += table[i]
end for
r = rand(sum)
for i = 1 to length(table)-1 do
r -= table[i]
if r <= 0 then
return i
end if
end for
return length(table)
end function
constant names = { "Rock", "Paper", "Scissors" } constant winner = { "We tied.", "Meself winned.", "You win." } integer user_action, my_action, key, win sequence user_rec, score user_rec = {1,1,1} score = {0,0}
while 1 do
my_action = remainder(weighted_rand(user_rec)+1,3)+1
puts(1,"Your choice [1-3]:\n")
puts(1," 1. Rock\n 2. Paper\n 3. Scissors\n> ")
key = -1
while (key < '1' or key > '3') and key != 'q' do
key = get_key()
end while
puts(1,key)
puts(1,'\n')
if key = 'q' then
exit
end if
user_action = key-'0'
win = remainder(my_action-user_action+3,3)
printf(1,"You chose %s; I chose %s. %s\n",
{ names[user_action],
names[my_action],
winner[win+1] })
if win then
score[win] += 1
end if
printf(1,"\nScore %d:%d\n",score)
user_rec[user_action] += 1
end while</lang>
Go
<lang go>package main
import (
"fmt" "rand" "strings" "time"
)
const rps = "rps"
var msg = []string{
"Rock breaks scissors", "Paper covers rock", "Scissors cut paper",
}
func main() {
rand.Seed(time.Nanoseconds())
fmt.Println("Rock Paper Scissors")
fmt.Println("Enter r, p, or s as your play. Anything else ends the game.")
fmt.Println("Running score shown as <your wins>:<my wins>")
var pi string // player input
var aScore, pScore int
sl := 3 // for output alignment
pcf := make([]int, 3) // pcf = player choice frequency
var plays int
aChoice := rand.Intn(3) // ai choice for first play is completely random
for {
// get player choice
fmt.Print("Play: ")
_, err := fmt.Scanln(&pi) // lazy
if err != nil || len(pi) != 1 {
break
}
pChoice := strings.Index(rps, pi)
if pChoice < 0 {
break
}
pcf[pChoice]++
plays++
// show result of play
fmt.Printf("My play:%s%c. ", strings.Repeat(" ", sl-2), rps[aChoice])
switch (aChoice - pChoice + 3) % 3 {
case 0:
fmt.Println("Tie.")
case 1:
fmt.Printf("%s. My point.\n", msg[aChoice])
aScore++
case 2:
fmt.Printf("%s. Your point.\n", msg[pChoice])
pScore++
}
// show score
sl, _ = fmt.Printf("%d:%d ", pScore, aScore)
// compute ai choice for next play
switch rn := rand.Intn(plays); {
case rn < pcf[0]:
aChoice = 1
case rn < pcf[0]+pcf[1]:
aChoice = 2
default:
aChoice = 0
}
}
}</lang> Sample output:
Rock Paper Scissors Enter r, p, or s as your play. Anything else ends the game. Running score shown as <your wins>:<my wins> Play: r My play: r. Tie. 0:0 Play: p My play: p. Tie. 0:0 Play: s My play: p. Scissors cut paper. Your point. 1:0 Play: r My play: p. Paper covers rock. My point. 1:1 Play: r My play: r. Tie. 1:1 Play: r My play: p. Paper covers rock. My point. 1:2 Play:
Icon and Unicon
The key to this comes down to two structures and two lines of code. The player history historyP is just an ordered list of every player turn and provides the weight for the random selection. The beats list is used to rank moves and to choose the move that would beat the randomly selected move. <lang Icon>link printf
procedure main()
printf("Welcome to Rock, Paper, Scissors.\n_
Rock beats scissors, Scissors beat paper, and Paper beats rock.\n\n")
historyP := ["rock","paper","scissors"] # seed player history winP := winC := draws := 0 # totals
beats := ["rock","scissors","paper","rock"] # what beats what 1 apart
repeat {
printf("Enter your choice or rock(r), paper(p), scissors(s) or quit(q):")
turnP := case map(read()) of {
"q"|"quit": break
"r"|"rock": "rock"
"p"|"paper": "paper"
"s"|"scissors": "scissors"
default: printf(" - invalid choice.\n") & next
}
turnC := beats[(?historyP == beats[i := 2 to *beats],i-1)] # choose move
put(historyP,turnP) # record history
printf("You chose %s, computer chose %s",turnP,turnC)
(beats[p := 1 to *beats] == turnP) &
(beats[c := 1 to *beats] == turnC) & (abs(p-c) <= 1) # rank play
if p = c then
printf(" - draw (#%d)\n",draws +:= 1 )
else if p > c then
printf(" - player win(#%d)\n",winP +:= 1)
else
printf(" - computer win(#%d)\n",winC +:= 1)
}
printf("\nResults:\n %d rounds\n %d Draws\n %d Computer wins\n %d Player wins\n",
winP+winC+draws,draws,winC,winP)
end</lang>
Sample output:
Welcome to Rock, Paper, Scissors. Rock beats scissors, Scissors beat paper, and Paper beats rock. Enter your choice or rock(r), paper(p), scissors(s) or quit(q):s You chose scissors, computer chose scissors - draw (#1) Enter your choice or rock(r), paper(p), scissors(s) or quit(q):p You chose paper, computer chose paper - draw (#2) Enter your choice or rock(r), paper(p), scissors(s) or quit(q):r You chose rock, computer chose scissors - computer win(#1) Enter your choice or rock(r), paper(p), scissors(s) or quit(q):r You chose rock, computer chose rock - draw (#3) Enter your choice or rock(r), paper(p), scissors(s) or quit(q):p You chose paper, computer chose paper - draw (#4) Enter your choice or rock(r), paper(p), scissors(s) or quit(q):s You chose scissors, computer chose scissors - draw (#5) Enter your choice or rock(r), paper(p), scissors(s) or quit(q):r You chose rock, computer chose rock - draw (#6) Enter your choice or rock(r), paper(p), scissors(s) or quit(q):r You chose rock, computer chose paper - player win(#1) Enter your choice or rock(r), paper(p), scissors(s) or quit(q):q Results: 8 rounds 6 Draws 1 Computer wins 1 Player wins
J
<lang j>require'misc strings' game=:3 :0
outcomes=. rps=. 0 0 0
choice=. 1+?3
while.#response=. prompt' Choose Rock, Paper or Scissors: ' do.
playerchoice=. 1+'rps' i. tolower {.deb response
if.4 = choice do.
smoutput 'Unknown response.'
smoutput 'Enter an empty line to quit'
continue.
end.
smoutput ' I choose ',choice {::;:'. Rock Paper Scissors'
smoutput (wintype=. 3 | choice-playerchoice) {:: 'Draw';'I win';'You win'
outcomes=. outcomes+0 1 2 = wintype
rps=. rps+1 2 3=playerchoice
choice=. 1+3|(?0) I.~ (}:%{:)+/\ 0, rps
end.
('Draws:','My wins:',:'Your wins: '),.":,.outcomes
)</lang>
Example use (playing to give the computer implementation the advantage):
<lang j> game
Choose Rock, Paper or Scissors: rock I choose Scissors
You win
Choose Rock, Paper or Scissors: rock I choose Paper
I win
Choose Rock, Paper or Scissors: rock I choose Paper
I win
Choose Rock, Paper or Scissors: rock I choose Paper
I win
Choose Rock, Paper or Scissors: rock I choose Paper
I win
Choose Rock, Paper or Scissors:
Draws: 0 My wins: 4 Your wins: 1</lang>
Java
This could probably be made simpler, but some more complexity is necessary so that other items besides rock, paper, and scissors can be added (as school children and nerds like to do [setup for rock-paper-scissors-lizard-spock is in multi-line comments]). The method getAIChoice() borrows from the Ada example in spirit, but is more generic to additional items.
<lang java5>import java.util.Arrays;
import java.util.EnumMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
import java.util.Random;
public class RPS { public enum Item{ ROCK, PAPER, SCISSORS, /*LIZARD, SPOCK*/; public List<Item> losesToList; public boolean losesTo(Item other) { return losesToList.contains(other); } static { SCISSORS.losesToList = Arrays.asList(ROCK/*, SPOCK*/); ROCK.losesToList = Arrays.asList(PAPER/*, SPOCK*/); PAPER.losesToList = Arrays.asList(SCISSORS/*, LIZARD*/); /* SPOCK.losesToList = Arrays.asList(PAPER, LIZARD); LIZARD.losesToList = Arrays.asList(SCISSORS, ROCK); */
}
} //EnumMap uses a simple array under the hood public final Map<Item, Integer> counts = new EnumMap<Item, Integer>(Item.class){{ for(Item item:Item.values()) put(item, 1); }};
private int totalThrows = Item.values().length;
public static void main(String[] args){ RPS rps = new RPS(); rps.run(); }
public void run() { Scanner in = new Scanner(System.in); System.out.print("Make your choice: "); while(in.hasNextLine()){ Item aiChoice = getAIChoice(); String input = in.nextLine(); Item choice; try{ choice = Item.valueOf(input.toUpperCase()); }catch (IllegalArgumentException ex){ System.out.println("Invalid choice"); continue; } counts.put(choice, counts.get(choice) + 1); totalThrows++; System.out.println("Computer chose: " + aiChoice); if(aiChoice == choice){ System.out.println("Tie!"); }else if(aiChoice.losesTo(choice)){ System.out.println("You chose...wisely. You win!"); }else{ System.out.println("You chose...poorly. You lose!"); } System.out.print("Make your choice: "); } }
private static final Random rng = new Random(); private Item getAIChoice() { int rand = rng.nextInt(totalThrows); for(Map.Entry<Item, Integer> entry:counts.entrySet()){ Item item = entry.getKey(); int count = entry.getValue(); if(rand < count){ List<Item> losesTo = item.losesToList; return losesTo.get(rng.nextInt(losesTo.size())); } rand -= count; } return null; } }</lang> Sample output:
Make your choice: rock Computer chose: PAPER You chose...poorly. You lose! Make your choice: rock Computer chose: SCISSORS You chose...wisely. You win! Make your choice: rock Computer chose: PAPER You chose...poorly. You lose! Make your choice: rock Computer chose: SCISSORS You chose...wisely. You win! Make your choice: rock Computer chose: PAPER You chose...poorly. You lose! Make your choice: rock Computer chose: ROCK Tie! Make your choice: rock Computer chose: ROCK Tie! Make your choice: rock Computer chose: PAPER You chose...poorly. You lose! Make your choice: rock Computer chose: PAPER You chose...poorly. You lose! Make your choice: rock Computer chose: PAPER You chose...poorly. You lose! Make your choice: scissors Computer chose: PAPER You chose...wisely. You win! Make your choice: scissors Computer chose: PAPER You chose...wisely. You win! ...
Liberty BASIC
<lang lb> dim rps( 2), g$( 3)
g$( 0) ="rock": g$( 1) ="paper": g$( 2) ="scissors" global total
total =0: draw =0: pwin =0: cwin =0
rps( 0) =1: rps( 1) =1: rps( 2) =1 ' at first computer will play all three with equal probability
c =int( 3 *rnd( 1)) ' first time, computer response is random
' In the following code we set three integer %ages for the <human>'s biassed throws.
' set up the <human> player's key frequencies as %ages.
' Done like this it's easy to mimic the <human> input of q$
' It allows only integer %age frequency- not an important thing.
rockP =45 ' <<<<<<<<< Set here the <human>'s %age of 'rock' choices. for i =1 to rockP: qF$ =qF$ +"R": next i
paprP =24 ' <<<<<<<<< Set here the %age of 'paper' choices. for i =1 to paprP: qF$ =qF$ +"P": next i
scisP =100 -rockP -paprP ' <<<<<<<<< %age 'scissors' calculated to make 100% for i =1 to scisP: qF$ =qF$ +"S": next i 'print qF$
do
'do: input q$:loop until instr( "RPSrpsQq", q$) ' for actual human input... possibly biassed. <<<<<<<<<<<<< REM one or the other line... q$ =mid$( qF$, int( 100 *rnd( 1)), 1) ' simulated <human> input with controlled bias. <<<<<<<<<<<<<
if total >10000 then q$ ="Q"
g =int( ( instr( "RrPpSsQq", q$) -1) / 2) if g >2 then [endGame]
total =total +1 rps( g) =rps( g) +1 ' accumulate plays the <human> has chosen. ( & hence their (biassed?) frequencies.) 'print " You chose "; g$( g); " and I chose "; g$( c); ". "
select case g -c
case 0
draw =draw +1 ':print "It's a draw"
case 1, -2
pwin =pwin +1 ':print "You win!"
case -1, 2
cwin =cwin +1 ':print "I win!"
end select
r =int( total *rnd( 1)) ' Now select computer's choice for next confrontation.
select case ' Using the accumulating data about <human>'s frequencies so far.
case r <=rps( 0)
c =1
case r <=( rps( 0) +rps( 1))
c =2
case else
c =0
end select
scan
loop until 0
[endGame]
print print " You won "; pwin; ", and I won "; cwin; ". There were "; draw; " draws." if cwin >pwin then print " I AM THE CHAMPION!!" else print " You won this time." print print " At first I assumed you'd throw each equally often." print " This means I'd win 1 time in 3; draw 1 in 3; lose 1 in 3." print " However if I detect a bias in your throws,...." print " ....this allows me to anticipate your most likely throw & on average beat it." print print " In fact, keyboard layout & human frailty mean even if you TRY to be even & random..." print " ... you may be typing replies with large bias. In 100 tries I gave 48 'P's, 29 'R' & 23 'S'!" print print " This time I played.." print " Rock "; using( "##.##", rps( 2)* 100 /total); "% Paper "; using( "##.##", rps( 0) *100 /total); "% Scissors "; using( "##.##", rps( 1) *100 /total); "%." print print " ( PS. I have since learned your actual bias had been.." print " Rock "; using( "##.##", rockP); "% Paper "; using( "##.##", paprP ); "% Scissors "; using( "##.##", ( 100 -rockP -paprP)); "%.)" print print " The advantage I can gain gets bigger the further the 'human' entries are biassed." print " The results statistically smooth out better with large runs." print " Try 10,000,000, & have a cuppa while you wait." print print " Can you see what will happen if, say, the 'human' is set to give 'Rock' EVERY time?" print " Try different %ages by altering the marked code lines." print print " Thanks for playing!" end
</lang>
You won 3204, and I won 3669. There were 3128 draws.
I AM THE CHAMPION!!
At first I assumed you'd throw each equally often.
This means I'd win 1 time in 3; draw 1 in 3; lose 1 in 3.
However if I detect a bias in your throws,....
....this allows me to anticipate your most likely throw & on average beat it.
In fact, keyboard layout & human frailty mean even if you TRY to be even & random...
... you may be typing replies with large bias. In 100 tries I gave 48 'P's, 29 'R' & 23 'S'!
This time I played..
Rock 30.17% Paper 45.93% Scissors 23.94%.
( PS. I have since learned your actual bias had been..
Rock 45.00% Paper 24.00% Scissors 31.00%.)
The advantage I can gain gets bigger the further the 'human' entries are biassed.
The results statistically smooth out better with large runs.
Try 10,000,000, & have a cuppa while you wait.
Can you see what will happen if, say, the 'human' is set to give 'Rock' EVERY time?
Try different %ages by altering the marked code lines.
OCaml
<lang OCaml> let pf = Printf.printf ;;
let looses a b = match a, b with
`R, `P -> true | `P, `S -> true | `S, `R -> true | _, _ -> false ;;
let rec get_move () =
pf "[R]ock, [P]aper, [S]cisors [Q]uit? " ;
match String.uppercase (read_line ()) with
"P" -> `P
| "S" -> `S
| "R" -> `R
| "Q" -> exit 0
| _ -> get_move () ;;
let str_of_move = function
`P -> "paper"
| `R -> "rock"
| `S -> "scisors" ;;
let comp_move r p s =
let tot = r +. p +. s in
let n = Random.float 1.0 in
if n < r /. tot then
`R
else
if n < (r +. p) /. tot then
`P
else
`S ;;
let rec make_moves r p s =
let cm = comp_move r p s in (* Computer move is based on game history. *)
let hm = get_move () in (* Human move is requested. *)
pf "Me: %s. You: %s. " (str_of_move cm) (str_of_move hm);
let outcome =
if looses hm cm then
"I win. You loose.\n"
else if cm = hm then
"We draw.\n"
else
"You win. I loose.\n"
in pf "%s" outcome;
match hm with (* Play on with adapted strategy. *)
`S -> make_moves (r +. 1.) p s
| `R -> make_moves r (p +. 1.) s
| `P -> make_moves r p (s +. 1.) ;;
(* Main loop. *) make_moves 1. 1. 1. ;;
</lang>
Perl 6
This is slightly more complicated than it could be; it is a general case framework with input filtering. It weights the computers choices based on your previous choices. Type in at least the first two characters of your choice, or just hit enter to quit. Customize it by supplying your own %vs options/outcomes.
Here is standard Rock-Paper-Scissors.
<lang perl6>my %vs = (
options => [<Rock Paper Scissors>],
ro => {
ro => [ 2, ],
pa => [ 1, 'Paper covers Rock: ' ],
sc => [ 0, 'Rock smashes Scissors: ' ]
},
pa => {
ro => [ 0, 'Paper covers Rock: ' ],
pa => [ 2, ],
sc => [ 1, 'Scissors cut Paper: ' ]
},
sc => {
ro => [ 1, 'Rock smashes Scissors: '],
pa => [ 0, 'Scissors cut Paper: ' ],
sc => [ 2, ]
}
);
my %choices = %vs<options>.map({; $_.substr(0,2).lc => $_ }); my $keys = %choices.keys.join('|'); my $prompt = %vs<options>.map({$_.subst(/(\w\w)/,->$/{"[$0]"})}).join(' ')~"? "; my %weight = %choices.keys »=>» 1;
my @stats = 0,0,0; my $round;
while my $player = (prompt "Round {++$round}: " ~ $prompt).lc {
$player.=substr(0,2);
say 'Invalid choice, try again.' and $round-- and next
unless $player.chars == 2 and $player ~~ /<$keys>/;
my $computer = %weight.keys.map( { $_ xx %weight{$_} } ).pick;
%weight{$_.key}++ for %vs{$player}.grep( { $_.value[0] == 1 } );
my $result = %vs{$player}{$computer}[0];
@stats[$result]++;
say "You chose %choices{$player}, Computer chose %choices{$computer}.";
print %vs{$player}{$computer}[1];
print ( 'You win!', 'You Lose!','Tie.' )[$result];
say " - (W:{@stats[0]} L:{@stats[1]} T:{@stats[2]})\n",
};</lang>Example output:
Round 1: [Ro]ck [Pa]per [Sc]issors? ro You chose Rock, Computer chose Paper. Paper covers Rock: You Lose! - (W:0 L:1 T:0) Round 2: [Ro]ck [Pa]per [Sc]issors? pa You chose Paper, Computer chose Scissors. Scissors cut Paper: You Lose! - (W:0 L:2 T:0) Round 3: [Ro]ck [Pa]per [Sc]issors? pa You chose Paper, Computer chose Scissors. Scissors cut Paper: You Lose! - (W:0 L:3 T:0) Round 4: [Ro]ck [Pa]per [Sc]issors? ro You chose Rock, Computer chose Rock. Tie. - (W:0 L:3 T:1) Round 5: [Ro]ck [Pa]per [Sc]issors? sc You chose Scissors, Computer chose Scissors. Tie. - (W:0 L:3 T:2) ...
Here is example output from the same code only with a different %vs data structure implementing Rock-Paper-Scissors-Lizard-Spock.
<lang perl6>my %vs = (
options => [<Rock Paper Scissors Lizard Spock>],
ro => {
ro => [ 2, ],
pa => [ 1, 'Paper covers Rock: ' ],
sc => [ 0, 'Rock smashes Scissors: ' ],
li => [ 0, 'Rock crushes Lizard: ' ],
sp => [ 1, 'Spock vaporizes Rock: ' ]
},
pa => {
ro => [ 0, 'Paper covers Rock: ' ],
pa => [ 2, ],
sc => [ 1, 'Scissors cut Paper: ' ],
li => [ 1, 'Lizard eats Paper: ' ],
sp => [ 0, 'Paper disproves Spock: ' ]
},
sc => {
ro => [ 1, 'Rock smashes Scissors: ' ],
pa => [ 0, 'Scissors cut Paper: ' ],
sc => [ 2, ],
li => [ 0, 'Scissors decapitate Lizard: '],
sp => [ 1, 'Spock smashes Scissors: ' ]
},
li => {
ro => [ 1, 'Rock crushes Lizard: ' ],
pa => [ 0, 'Lizard eats Paper: ' ],
sc => [ 1, 'Scissors decapitate Lizard: '],
li => [ 2, ],
sp => [ 0, 'Lizard poisons Spock: ' ]
},
sp => {
ro => [ 0, 'Spock vaporizes Rock: ' ],
pa => [ 1, 'Paper disproves Spock: ' ],
sc => [ 0, 'Spock smashes Scissors: ' ],
li => [ 1, 'Lizard poisons Spock: ' ],
sp => [ 2, ]
}
);</lang>
Round 1: [Ro]ck [Pa]per [Sc]issors [Li]zard [Sp]ock? li You chose Lizard, Computer chose Scissors. Scissors decapitate Lizard: You Lose! - (W:0 L:1 T:0) Round 2: [Ro]ck [Pa]per [Sc]issors [Li]zard [Sp]ock? sp You chose Spock, Computer chose Paper. Paper disproves Spock: You Lose! - (W:0 L:2 T:0) Round 3: [Ro]ck [Pa]per [Sc]issors [Li]zard [Sp]ock? ro You chose Rock, Computer chose Lizard. Rock crushes Lizard: You Win! - (W:1 L:2 T:0) Round 4: [Ro]ck [Pa]per [Sc]issors [Li]zard [Sp]ock? ro You chose Rock, Computer chose Scissors. Rock smashes Scissors: You win! - (W:2 L:2 T:0) Round 5: [Ro]ck [Pa]per [Sc]issors [Li]zard [Sp]ock? li You chose Lizard, Computer chose Paper. Lizard eats Paper: You win! - (W:3 L:2 T:0) ...
PicoLisp
<lang PicoLisp>(use (C Mine Your)
(let (Rock 0 Paper 0 Scissors 0)
(loop
(setq Mine
(let N (if (gt0 (+ Rock Paper Scissors)) (rand 1 @) 0)
(seek
'((L) (le0 (dec 'N (caar L))))
'(Rock Paper Scissors .) ) ) )
(prin "Enter R, P or S to play, or Q to quit: ")
(loop
(and (= "Q" (prinl (setq C (uppc (key))))) (bye))
(T (setq Your (find '((S) (pre? C S)) '(Rock Paper Scissors))))
(prinl "Bad input - try again") )
(prinl
"I say " (cadr Mine) ", You say " Your ": "
(cond
((== Your (cadr Mine)) "Draw")
((== Your (car Mine)) "I win")
(T "You win") ) )
(inc Your) ) ) )</lang>
Python
<lang python>#!/usr/bin/python from random import choice, randrange from bisect import bisect from collections import defaultdict
WHATBEATS = { 'paper' : 'scissors',
'scissors' : 'rock',
'rock' : 'paper' }
ORDER = ('rock', 'paper', 'scissors')
CHOICEFREQUENCY = defaultdict(int)
def probChoice(choices, probabilities):
total = sum(probabilities)
prob_accumulator = 0
accumulator = []
for p in probabilities:
prob_accumulator += p
accumulator.append(prob_accumulator)
r = randrange(total)
bsct = bisect(accumulator, r)
chc = choices[bsct]
return chc
def checkWinner(a, b):
if b == WHATBEATS[a]:
return b
elif a == WHATBEATS[b]:
return a
return None
def sanitizeChoice(a):
# Drop it to lower-case return a.lower()
def registerPlayerChoice(choice):
CHOICEFREQUENCY[choice] += 1
def getRandomChoice():
if len(CHOICEFREQUENCY) == 0:
return choice(ORDER)
choices = CHOICEFREQUENCY.keys()
probabilities = CHOICEFREQUENCY.values()
return WHATBEATS[probChoice(choices, probabilities)]
while True:
humanChoice = raw_input()
humanChoice = sanitizeChoice(humanChoice)
if humanChoice not in ORDER:
continue
compChoice = getRandomChoice() print "Computer picked", compChoice+",",
# Don't register the player choice until after the computer has made # its choice. registerPlayerChoice(humanChoice)
winner = checkWinner(humanChoice, compChoice)
if winner == None:
winner = "nobody"
print winner, "wins!"</lang>
Output, where player always chooses Rock:
!504 #5 j0 ?0 $ ./rps.py rock Computer picked scissors, rock wins! rock Computer picked paper, paper wins! rock Computer picked paper, paper wins! rock Computer picked paper, paper wins! rock Computer picked paper, paper wins!
Ruby
<lang ruby>class RockPaperScissorsGame
def initialize()
@pieces = %w[rock paper scissors]
@beats = {
'rock' => 'paper',
'paper' => 'scissors',
'scissors' => 'rock',
}
@plays = {
'rock' => 1,
'paper' => 1,
'scissors' => 1,
}
@score = [0, 0]
play end
def humanPlay()
answer = nil
loop do
print "\nYour choice: #@pieces? "
answer = STDIN.gets.strip.downcase
next if answer.empty?
if idx = @pieces.find_index {|piece| piece.match(/^#{answer}/)}
answer = @pieces[idx]
break
else
puts "invalid answer, try again"
end
end
answer
end
def computerPlay()
total = @plays.values.reduce(:+)
r = rand(total) + 1
sum = 0
humans_choice = nil
@pieces.each do |piece|
sum += @plays[piece]
if r <= sum
humans_choice = piece
break
end
end
@beats[humans_choice]
end
def play
loop do
h = humanPlay
c = computerPlay
print "H: #{h}, C: #{c} => "
# only update the human player's history after the computer has chosen
@plays[h] += 1
if h == c
puts "draw"
elsif h == @beats[c]
puts "Human wins"
@score[0] += 1
else
puts "Computer wins"
@score[1] += 1
end
puts "score: human=#{@score[0]}, computer=#{@score[1]}"
end
end
end
game = RockPaperScissorsGame.new</lang> sample game where human always chooses rock:
Your choice: ["rock", "paper", "scissors"]? r H: rock, C: rock => draw score: human=0, computer=0 Your choice: ["rock", "paper", "scissors"]? r H: rock, C: paper => Computer wins score: human=0, computer=1 Your choice: ["rock", "paper", "scissors"]? r H: rock, C: rock => draw score: human=0, computer=1 Your choice: ["rock", "paper", "scissors"]? r H: rock, C: paper => Computer wins score: human=0, computer=2 Your choice: ["rock", "paper", "scissors"]? r H: rock, C: paper => Computer wins score: human=0, computer=3 Your choice: ["rock", "paper", "scissors"]? r H: rock, C: paper => Computer wins score: human=0, computer=4 Your choice: ["rock", "paper", "scissors"]? r H: rock, C: paper => Computer wins score: human=0, computer=5 Your choice: ["rock", "paper", "scissors"]? r H: rock, C: paper => Computer wins score: human=0, computer=6 Your choice: ["rock", "paper", "scissors"]? r H: rock, C: paper => Computer wins score: human=0, computer=7 Your choice: ["rock", "paper", "scissors"]? r H: rock, C: paper => Computer wins score: human=0, computer=8 Your choice: ["rock", "paper", "scissors"]? r H: rock, C: paper => Computer wins score: human=0, computer=9 Your choice: ["rock", "paper", "scissors"]? r H: rock, C: paper => Computer wins score: human=0, computer=10
Tcl
<lang tcl>package require Tcl 8.5
- Choices are represented by integers, which are indices into this list:
- Rock, Paper, Scissors
- Normally, idiomatic Tcl code uses names for these sorts of things, but it
- turns out that using integers simplifies the move-comparison logic.
- How to ask for a move from the human player
proc getHumanMove {} {
while 1 {
puts -nonewline "Your move? \[R\]ock, \[P\]aper, \[S\]cissors: " flush stdout gets stdin line if {[eof stdin]} { puts "\nBye!" exit } set len [string length $line] foreach play {0 1 2} name {"rock" "paper" "scissors"} { # Do a prefix comparison if {$len && [string equal -nocase -length $len $line $name]} { return $play } } puts "Sorry, I don't understand that. Try again please."
}
}
- How to ask for a move from the machine player
proc getMachineMove {} {
global states
set choice [expr {int(rand() * [::tcl::mathop::+ {*}$states 3])}]
foreach play {1 2 0} count $states {
if {[incr sum [expr {$count+1}]] > $choice} { puts "I play \"[lindex {Rock Paper Scissors} $play]\"" return $play }
}
}
- Initialize some state variables
set states {0 0 0} set humanWins 0 set machineWins 0
- The main game loop
while 1 {
# Get the moves for this round
set machineMove [getMachineMove]
set humanMove [getHumanMove]
# Report on what happened
if {$humanMove == $machineMove} {
puts "A draw!"
} elseif {($humanMove+1)%3 == $machineMove} {
puts "I win!" incr machineWins
} else {
puts "You win!" incr humanWins
}
puts "Cumulative scores: $humanWins to you, $machineWins to me"
# Update the state of how the human has played in the past
lset states $humanMove [expr {[lindex $states $humanMove] + 1}]
}</lang> Sample run:
Your move? [R]ock, [P]aper, [S]cissors: rock I play "Scissors" You win! Cumulative scores: 1 to you, 0 to me Your move? [R]ock, [P]aper, [S]cissors: r I play "Paper" I win! Cumulative scores: 1 to you, 1 to me Your move? [R]ock, [P]aper, [S]cissors: s I play "Paper" You win! Cumulative scores: 2 to you, 1 to me Your move? [R]ock, [P]aper, [S]cissors: sciss I play "Paper" You win! Cumulative scores: 3 to you, 1 to me Your move? [R]ock, [P]aper, [S]cissors: p I play "Paper" A draw! Cumulative scores: 3 to you, 1 to me Your move? [R]ock, [P]aper, [S]cissors: zaphod beeblebrox Sorry, I don't understand that. Try again please. Your move? [R]ock, [P]aper, [S]cissors: r I play "Scissors" You win! Cumulative scores: 4 to you, 1 to me Your move? [R]ock, [P]aper, [S]cissors: ^D Bye!