Nim game
You are encouraged to solve this task according to the task description, using any language you may know.
Nim is a simple game where the second player─if they know the trick─will always win.
The game has only 3 rules:
 start with 12 tokens
 each player takes 1, 2, or 3 tokens in turn
 the player who takes the last token wins.
To win every time, the second player simply takes 4 minus the number the first player took. So if the first player takes 1, the second takes 3; if the first player takes 2, the second should take 2; and if the first player takes 3, the second player will take 1.
 Task
Design a simple Nim game where the human player goes first, and the computer always wins. The game should enforce the rules.
11l
V tokens = 12
F getTokens(curTokens) > N
print(‘How many tokens would you like to take? ’, end' ‘’)
V take = Int(input())
I (take < 1  take > 3)
print("Number must be between 1 and 3.\n")
getTokens(curTokens)
R
:tokens = curTokens  take
print(‘You take #. tokens.’.format(take))
print("#. tokens remaining.\n".format(:tokens))
F compTurn(curTokens)
V take = curTokens % 4
:tokens = curTokens  take
print(‘Computer takes #. tokens.’.format(take))
print("#. tokens remaining.\n".format(:tokens))
L tokens > 0
getTokens(tokens)
compTurn(tokens)
print(‘Computer wins!’)
 Output:
How many tokens would you like to take? 2 You take 2 tokens. 10 tokens remaining. Computer takes 2 tokens. 8 tokens remaining. How many tokens would you like to take? 1 You take 1 tokens. 7 tokens remaining. Computer takes 3 tokens. 4 tokens remaining. How many tokens would you like to take? 3 You take 3 tokens. 1 tokens remaining. Computer takes 1 tokens. 0 tokens remaining. Computer wins!
8080 Assembly
It may not be a very interesting game, but it assembles to only 222 bytes.
bdos: equ 5 ; CP/M syscalls
puts: equ 9
putch: equ 2
getch: equ 1
maxtokens: equ 12 ; you can change this for more tokens
org 100h
lxi d,nim
call outs
mvi b,maxtokens ; 12 tokens
gameloop: lxi d,tokens ; Show tokens
call outs
mov c,b
showtokens: dcr c
jm tokensdone
mvi a,''
call outa
jmp showtokens
tokensdone: lxi d,nl
call outs
lxi d,prompt ; Show prompt
call outs
readinput: call ina ; Read input
sui '1' ; Subtract '1' (lowest acceptable
jc wrong ; input)
cpi 3 ; range of values is [0..2]
jnc wrong
cmp b ; can't take more than there are either
jnc wrong
cma ; negate; a = ~(a1)
mov c,a ; keep value
add b ; subtract from tokens
mov b,a
mvi a,4 ; computer take 4X tokens
add c
mov c,a
lxi d,response ; print how many I take
call outs
mvi a,'0'
add c
call outa
mov a,b ; subtract the ones I take
sub c
jz done ; if I took the last one, I won
mov b,a
lxi d,nl
call outs
call outs
jmp gameloop
done: lxi d,lose ; there's no win condition
jmp outs
;; Invalid input
wrong: lxi d,wronginp
call outs
jmp readinput
;; Read character into A and keep registers
ina: push b
push d
push h
mvi c,getch
call bdos
jmp restore
;; Print A and keep registers
outa: push b
push d
push h
mvi c,putch
mov e,a
call bdos
jmp restore
;; Print string and keep registers
outs: push b
push d
push h
mvi c,puts
call bdos
;; Restore registers
restore: pop h
pop d
pop b
ret
nim: db 'Nim',13,10,13,10,'$'
prompt: db 'How many will you take (13)? $'
response: db 13,10,'I take $'
tokens: db 'Tokens: $'
lose: db 13,10,'You lose!$'
nl: db 13,10,'$'
wronginp: db 8,7,32,8,'$' ; beep and erase choice
8086 Assembly
This is a decent demonstration of the greater versatility of the 8086
when compared to the 8080. Where the 8080 only allowed complex operations
on its A
register, the other registers being limited to
loading, incrementing and decrementing, the 8086 allows most operations to use
any registers as its operands, leading to much shorter assembly code for the same
program.
The tradeoff is a more complex instruction encoding, usually requiring two
bytes per instruction, minus any immediate operands. But that is ultimately
worth it: whereas the 8080 version takes 222 bytes, this 8086 Nim assembles to
only 173 bytes, mostly as a result of the threeinstruction pattern of "load data into A
, do something with it, then store it elsewhere" simplifying to just one instruction to manipulate
the data in place.
;; MSDOS Nim; assembles with nasm.
bits 16
cpu 8086
getch: equ 1
putch: equ 2
puts: equ 9 ; INT 21h calls
maxtokens: equ 12 ; Amount of tokens there are
section .text
org 100h
mov dx,nim ; Print signon
call outs
mov ch,maxtokens ; CH = amount of tokens we have
loop: mov dx,tokens ; Tokens: ...
call outs
mov ah,putch ; Print a  for each token
mov dl,''
mov dh,ch
puttoks: int 21h
dec dh
jnz puttoks
mov dx,prompt ; Ask the user how many to take
call outs
ask: mov ah,getch ; Read keypress
int 21h
sub al,'1' ; Make number (minus one)
jc bad ; Carry, it was <1 (bad)
inc al ; Add 1 (because we subtracted '1')
cmp al,3
ja bad ; If it was >3, it is bad
cmp al,ch
ja bad ; If it was > amount left, it is bad
sub ch,al ; Remove your tokens from pile
mov cl,4 ; I take 4N, which is 3N1
sub cl,al
sub ch,cl ; Remove my tokens from pile
mov dx,response ; Tell the user how many I took.
call outs
mov dl,'0'
add dl,cl
mov ah,putch
int 21h
cmp ch,0 ; Are there any tokens left?
jne loop ; If not, prompt again
mov dx,lose ; But otherwise, you've lost
; Fall through into print string routine and then stop.
;; Print string in DX. (This saves a byte each CALL)
outs: mov ah,puts
int 21h
ret
;; Input is bad; beep, erase, ask again
bad: mov dx,wronginp
call outs
jmp ask
section .data
nim: db 'Nim$'
prompt: db 13,10,'How many will you take (13)? $'
response: db 13,10,'I take $'
tokens: db 13,10,13,10,'Tokens: $'
lose: db 13,10,'You lose!$'
wronginp: db 8,7,32,8,'$'
Action!
BYTE FUNC PlayerTurn(BYTE tokens)
BYTE t,max
IF tokens<3 THEN
max=tokens
ELSE
max=3
FI
DO
PrintF("How many tokens would you like to take (1%B)? ",max)
t=InputB()
UNTIL t>=1 AND t<=max
OD
PrintF("Player takes %B tokens.%E",t)
t=tokenst
IF t=0 THEN
PrintE("Player wins.")
FI
RETURN (t)
BYTE FUNC ComputerTurn(BYTE tokens)
BYTE t
t=tokens MOD 4
PrintF("Computer takes %B tokens.%E",t)
t=tokenst
IF t=0 THEN
PrintE("Computer wins.")
FI
RETURN (t)
PROC Main()
BYTE tokens=[12],t
BYTE player=[1]
WHILE tokens>0
DO
PrintF("Available tokens: %B%E",tokens)
IF player THEN
tokens=PlayerTurn(tokens)
ELSE
tokens=ComputerTurn(tokens)
FI
player=1player
OD
RETURN
 Output:
Screenshot from Atari 8bit computer
Available tokens: 12 How many tokens would you like to take (13)? 3 Player takes 3 tokens. Available tokens: 9 Computer takes 1 tokens. Available tokens: 8 How many tokens would you like to take (13)? 2 Player takes 2 tokens. Available tokens: 6 Computer takes 2 tokens. Available tokens: 4 How many tokens would you like to take (13)? 1 Player takes 1 tokens. Available tokens: 3 Computer takes 3 tokens. Computer wins.
Ada
with Ada.Text_IO;
procedure Nim is
subtype Token_Range is Positive range 1 .. 3;
package TIO renames Ada.Text_IO;
package Token_IO is new TIO.Integer_IO(Token_Range);
procedure Get_Tokens(remaining : in Natural; how_many : out Token_Range) is
begin
loop
TIO.Put("How many tokens would you like to take? ");
begin
Token_IO.Get(TIO.Standard_Input, how_many);
exit when how_many < remaining;
raise Constraint_Error;
exception
when TIO.Data_Error  Constraint_Error =>
if not TIO.End_Of_Line(TIO.Standard_Input) then
TIO.Skip_Line(TIO.Standard_Input);
end if;
TIO.Put_Line("Invalid input.");
end;
end loop;
end;
tokens : Natural := 12;
how_many : Token_Range;
begin
loop
TIO.Put_Line(tokens'Img & " tokens remain.");
 no exit condition here: human cannot win.
Get_Tokens(tokens, how_many);
TIO.Put_Line("Human takes" & how_many'Img & " tokens.");
tokens := tokens  how_many;
 computer's turn: take the remaining N tokens to amount to 4.
how_many := tokens mod 4;
TIO.Put_Line("Computer takes" & how_many'Img & " tokens.");
tokens := tokens  how_many;
Ada.Text_IO.New_Line;
exit when tokens = 0;
end loop;
TIO.Put_Line("Computer won!");
end Nim;
 Output:
12 tokens remain. How many tokens would you like to take? a Invalid input. How many tokens would you like to take? 1 Human takes 1 tokens. Computer takes 3 tokens. 8 tokens remain. How many tokens would you like to take? 2 Human takes 2 tokens. Computer takes 2 tokens. 4 tokens remain. How many tokens would you like to take? 3 Human takes 3 tokens. Computer takes 1 tokens. Computer won!
ALGOL 68
BEGIN # play Nim #
# gets a single character answer from standin and returns it #
PROC answer = ( STRING prompt )CHAR:
BEGIN
STRING s;
INT left := 0;
WHILE print( ( prompt, "> " ) );
read( ( s, newline ) );
left := LWB s;
INT right := UPB s;
WHILE IF left > right THEN FALSE ELSE s[ left ] = " " FI DO left +:= 1 OD;
WHILE IF right < left THEN FALSE ELSE s[ right ] = " " FI DO right := 1 OD;
left /= right
DO
print( ( "Please reply with a single character", newline ) )
OD;
s[ left ]
END # answer # ;
# play one game #
INT tokens := 12;
STRING suffix := "";
WHILE
CHAR user;
WHILE user := answer( "There are "
+ whole( tokens, 0 )
+ " tokens"
+ suffix
+ ", how many do you want to take (1, 2 or 3)"
);
user /= "1" AND user /= "2" AND user /= "3"
DO
print( ( "please answer 1, 2 or 3", newline ) )
OD;
INT move = ABS user  ABS "0";
print( ( "I take ", whole( 4  move, 0 ), newline ) );
suffix := " left";
tokens := 4;
tokens > 0
DO SKIP OD;
print( ( "I win!", newline ) )
END
 Output:
There are 12 tokens, how many do you want to take (1, 2 or 3)> 3 I take 1 There are 8 tokens left, how many do you want to take (1, 2 or 3)> t please answer 1, 2 or 3 There are 8 tokens left, how many do you want to take (1, 2 or 3)> 4 please answer 1, 2 or 3 There are 8 tokens left, how many do you want to take (1, 2 or 3)> 1 I take 3 There are 4 tokens left, how many do you want to take (1, 2 or 3)> 2 I take 2 I win!
ALGOLM
BEGIN
PROCEDURE WELCOME;
BEGIN
WRITE("THE GAME OF NIM");
WRITE("");
WRITE("WE BEGIN WITH 12 TOKENS. ON EACH TURN, A");
WRITE("PLAYER MAY TAKE BETWEEN 1 AND 3 TOKENS.");
WRITE("THE PLAYER WHO TAKES THE LAST TOKEN WINS.");
WRITE("");
END;
PROCEDURE SHOW(N);
INTEGER N;
BEGIN
WRITE("REMAINING TOKENS:",N);
END;
INTEGER FUNCTION GETNUM(LOWLIM, TOPLIM);
INTEGER LOWLIM, TOPLIM;
BEGIN
INTEGER OK, N;
OK := 0;
WHILE OK = 0 DO
BEGIN
WRITE("YOU TAKE:");
READ(N);
IF N < LOWLIM OR N > TOPLIM THEN
BEGIN
WRITE("MUST TAKE BETWEEN",LOWLIM," AND",TOPLIM,".");
WRITE("TRY AGAIN.");
END
ELSE
OK := 1;
END;
GETNUM := N;
END;
INTEGER FUNCTION PLAY(PLAYER, TOKENS, TAKEN);
INTEGER PLAYER, TOKENS, TAKEN;
BEGIN
IF PLAYER = 1 THEN % HUMAN PLAYER'S MOVE %
TAKEN := GETNUM(1,3)
ELSE % MACHINE'S MOVE %
TAKEN := 4  TAKEN;
PLAY := TAKEN;
END;
PROCEDURE REPORT(WINNER);
INTEGER WINNER; % MACHINE = 0, HUMAN = 1 %
BEGIN
IF WINNER = 0 THEN
WRITE("I TOOK THE LAST ONE, SO I WIN. SORRY ABOUT THAT.")
ELSE
WRITE("YOU TOOK THE LAST ONE. YOU WIN. CONGRATULATIONS!");
END;
% MAIN CODE BEGINS HERE %
INTEGER PLAYER, TOKENS, TAKEN, HUMAN, MACHINE;
MACHINE := 0;
HUMAN := 1;
TOKENS := 12;
TAKEN := 0;
PLAYER := HUMAN;
WELCOME;
WRITE("YOU GO FIRST.");
WHILE TOKENS > 0 DO
BEGIN
SHOW(TOKENS);
TAKEN := PLAY(PLAYER, TOKENS, TAKEN);
TOKENS := TOKENS  TAKEN;
IF PLAYER = MACHINE THEN WRITE("I TOOK:",TAKEN);
IF TOKENS > 0 THEN PLAYER := 1  PLAYER;
END;
REPORT(PLAYER);
WRITE("THANKS FOR PLAYING!");
END
 Output:
THE GAME OF NIM WE BEGIN WITH 12 TOKENS. ON EACH TURN, A PLAYER MAY TAKE BETWEEN 1 AND 3 TOKENS. THE PLAYER WHO TAKES THE LAST TOKEN WINS. YOU GO FIRST. REMAINING TOKENS: 12 YOU TAKE: > 4 MUST TAKE BETWEEN 1 AND 3. TRY AGAIN. YOU TAKE: > 3 REMAINING TOKENS: 9 I TOOK: 1 REMAINING TOKENS: 8 YOU TAKE: >2 REMAINING TOKENS: 6 I TOOK: 2 REMAINING TOKENS: 4 YOU TAKE: > 1 REMAINING TOKENS: 3 I TOOK: 3 I TOOK THE LAST ONE, SO I WIN. SORRY ABOUT THAT. THANKS FOR PLAYING!
Arturo
total: 12
while ø [
tk: 0
print "YOUR turn:"
while [not? contains? 1..3 tk: <= to :integer input "How many tokens will you take? (13) "][]
total: totaltk
print [total "tokens remaining\n"]
print ["COMPUTER's turn:"]
print ["taking:" 4tk]
total: total(4tk)
print [total "tokens remaining\n"]
if total=0 [
print "COMPUTER won. :)"
break
]
]
 Output:
YOUR turn: How many tokens will you take? (13) 3 9 tokens remaining COMPUTER's turn: taking: 1 8 tokens remaining YOUR turn: How many tokens will you take? (13) 2 6 tokens remaining COMPUTER's turn: taking: 2 4 tokens remaining YOUR turn: How many tokens will you take? (13) 1 3 tokens remaining COMPUTER's turn: taking: 3 0 tokens remaining COMPUTER won. :)
AsciiDots
%$LMRTX
.$"Nim Dots"$""
/$_"Number must be "\
T /~\ 
*M /+*[o]  
R []\ .>#3+[>][<]1#<. 
.#12>^ \"stod "$#_$" ekat uoY"_$/ \**/ 
.>$_"How many dots would you like to take"#?/ 
\X X<".3 dna 1 neewteb"$/
/*L 
[]\ R 
 *$_"Computer takes "$_#$" dots"/
M*#4[%]
\/
/$"computer wins!"&
/~
*#0[=]
L**>$_#$" dots remaining."$""
T
 Output:
Nim Dots How many dots would you like to take?: 3 You take 3 dots 9 dots remaining. Computer takes 1 dots 8 dots remaining. How many dots would you like to take?: 1 You take 1 dots 7 dots remaining. Computer takes 3 dots 4 dots remaining. How many dots would you like to take?: 2 You take 2 dots 2 dots remaining. Computer takes 2 dots 0 dots remaining. computer wins!
AutoHotkey
Play:
tokens := 12
while tokens {
while !(D>0 && D<4)
InputBox, D, Nim Game, % "Tokens Remaining = " tokens
. "`nHow many tokens would you like to take?"
. "`nChoose 1, 2 or 3"
tokens = D
MsgBox % "Computer Takes " 4D
tokens = 4d, d:=0
}
MsgBox, 262212,,Computer Always Wins!`nWould you like to play again?
IfMsgBox, Yes
gosub Play
else
ExitApp
return
AWK
# syntax: GAWK f NIM_GAME.AWK
BEGIN {
tokens = 12
printf("Nim game  using %d tokens\n",tokens)
while (tokens > 0) {
for (;;) {
printf("how many tokens 13? ")
getline ans
if (ans ~ /^[123]$/) {
tokens = ans
prn("player")
break
}
print("invalid input, try again")
}
tokens = ans = tokens % 4
prn("computer")
}
print("computer wins")
exit(0)
}
function prn(who) {
printf("%s takes %d token%s; there are %d remaining\n",who,ans,(ans==1)?"":"s",tokens)
}
 Output:
Nim game  using 12 tokens how many tokens 13? 1 player takes 1 token; there are 11 remaining computer takes 3 tokens; there are 8 remaining how many tokens 13? 2 player takes 2 tokens; there are 6 remaining computer takes 2 tokens; there are 4 remaining how many tokens 13? 3 player takes 3 tokens; there are 1 remaining computer takes 1 token; there are 0 remaining computer wins
BASIC
Applesoft BASIC
This oneliner demonstrates the 240 character line limit. The program has been crafted to be exactly 244 characters long. The last 4 characters HEAP will be truncated from the last statement in the line. The HEAP variable is optional in the outmost NEXT statement so the program still runs correctly.
0ST$(0)="YOU MUST TAKE 1, 2, OR 3 TOKENS.":FORHEAP=12TO1STEP4:PRINT"THERE ARE "HEAP" TOKENS REMAINING.":FORI=0TO1:INPUT"HOW MANY WOULD YOU LIKE TO TAKE?";T%:I=T%>0ANDT%<4:PRINTST$(I):NEXTI:PRINT"ON MY TURN I WILL TAKE "4T%" TOKENS.":NEXTHEAP
BASIC256
monton = 12
llevar = 0
while monton > 0
print "There are "; monton; " tokens remaining. How many would you like to take? ";
input integer llevar
while llevar = 0 or llevar > 3
print "You must take 1, 2, or 3 tokens. How many would you like to take ";
input integer llevar
end while
print "On my turn I will take "; 4  llevar; " token(s)."
monton = monton  4
end while
print
print "I got the last token. I win! Better luck next time."
end
Craft Basic
let h = 12
label loop
alert "There are ", h ," tokens remaining."
input "How many would you like to take? ", t
if t > 3 or t < 1 then
alert "You must take between 1 to 3 tokens."
endif
if h  t < 0 then
alert "You cannot take that many. There's only ", h ," left."
endif
if t <= 3 and t >= 1 and h  t >= 0 then
let h = h  t
if h = 0 then
alert "Congratulations. You got the last token."
end
endif
let t = 4  t
if h >= 15 then
let t = 3
endif
if h <= 3 then
let t = h
endif
alert "I will take ", t ," tokens."
let h = h  t
if h = 0 then
alert "I got the last token. I win. Better luck next time."
end
endif
endif
goto loop
FreeBASIC
dim as ubyte heap=12, take
while heap > 0
print using "There are ## tokens remaining. How many would you like to take?"; heap
input take
while take=0 orelse take>3
print "You must take 1, 2, or 3 tokens. How many would you like to take?"
input take
wend
print using "On my turn I will take ## tokens."; 4take
heap = heap  4
wend
print "I got the last token. I win! Better luck next time."
FTCBASIC
define tokens = 12, take = 0
gosub intro
do
print "There are " \
print tokens \
print " tokens remaining."
crlf
print "How many would you like to take? " \
input take
if take > 3 or take < 1 then
print "You must take between 1 to 3 tokens."
endif
if tokens  take < 0 then
print "You cannot take that many."
endif
if take <= 3 and take >= 1 and tokens  take >= 0 then
let tokens = tokens  take
if tokens = 0 then
bell
print "Congratulations. You got the last token."
pause
end
endif
let take = 4  take
if tokens >= 15 then
let take = 3
endif
if tokens <= 3 then
let take = tokens
endif
print "I will take " \
print take \
print " of the tokens."
let tokens = tokens  take
if tokens = 0 then
print "I got the last token. I win. Better luck next time."
pause
end
endif
endif
loop
sub intro
cls
print "NIM game"
crlf
print "Press any key to play..."
cls
return
GWBASIC
10 HEAP = 12
20 WHILE HEAP>0
30 TAKE = 0
40 PRINT "There are ";HEAP;" tokens left."
50 WHILE TAKE < 1 OR TAKE > 3 OR TAKE > HEAP
60 INPUT "How many would you like to take? ", TAKE
70 IF TAKE = HEAP THEN GOTO 140
80 WEND
90 PRINT "I will take ";4TAKE;" tokens."
100 HEAP = HEAP  4
110 WEND
120 PRINT "I got the last token. Better luck next time."
130 END
140 PRINT "You got the last token. Congratulations!"
150 END
ISBASIC
100 PROGRAM "Nim.bas"
110 RANDOMIZE
120 CLEAR SCREEN
130 LET TOKENS=12
140 PRINT "Starting with";TOKENS;"tokens.":PRINT
150 DO
160 PRINT "How many tokens will you take? (13) ";
170 DO
180 LET K=VAL(INKEY$)
190 LOOP UNTIL K>0 AND K<4
200 LET TOKENS=MAX(TOKENSK,0):LET G=0
210 PRINT K:PRINT TAB(19);TOKENS;"remainig.":PRINT
220 IF TOKENS>0 THEN
230 LET L=MOD(TOKENS,4)
240 IF L=0 THEN LET L=MIN(RND(3)+1,TOKENS)
250 LET TOKENS=TOKENSL:LET G=1
260 PRINT "Computer takes";L;"tokens.";TOKENS;"remaining.":PRINT
270 END IF
280 LOOP WHILE TOKENS>0
290 IF G THEN
300 PRINT "Computer wins!"
310 ELSE
320 PRINT "You win!"
330 END IF
PureBasic
OpenConsole()
Define monton.i = 12, llevar.i
While monton > 0
Print("There are " + Str(monton) + " tokens remaining. How many would you like to take? ")
llevar = Val(Input())
While llevar = 0 Or llevar > 3
Print("You must take 1, 2, or 3 tokens. How many would you like to take ")
llevar = Val(Input())
Wend
PrintN("On my turn I will take " + Str(4  llevar) + " token(s).")
monton = monton  4
Wend
PrintN("I got the last token. I win! Better luck next time.")
PrintN(#CRLF$ + " terminado, pulsa RETURN"): Input()
CloseConsole()
QBasic
monton = 12
llevar = 0
DO WHILE monton > 0
PRINT USING "There are ## tokens remaining. How many would you like to take"; monton;
INPUT llevar
DO WHILE llevar = 0 OR llevar > 3
INPUT "You must take 1, 2, or 3 tokens. How many would you like to take"; llevar
LOOP
PRINT "On my turn I will take"; 4  llevar; " token(s)."
monton = monton  4
LOOP
PRINT
PRINT "I got the last token. I win! Better luck next time."
END
Run BASIC
monton = 12
llevar = 0
while monton > 0
input "There are "; monton; " tokens remaining. How many would you like to take? "; llevar
while llevar = 0 or llevar > 3
input "You must take 1, 2, or 3 tokens. How many would you like to take "; llevar
wend
print "On my turn I will take "; 4  llevar; " token(s)."
monton = monton  4
wend
print
print "I got the last token. I win! Better luck next time."
end
SBasic
$constant maxtokens = 12
$constant machine = 0
$constant human = 1
$constant false = 0
$constant true = 0FFFFH
procedure welcome
print "Welcome to the Game of Nim."
print "We begin with";maxtokens;" tokens. On each turn, a player"
print "may take between 1 and 3 tokens. The player who takes the"
print "last token wins."
print
end
procedure show(n = integer)
var i = integer
print "Available tokens:";n;" ";
rem  provide a visual display
for i = 1 to n
print "o ";
next i
print
end
function getnum(lowlim, toplim = integer) = integer
var ok, n = integer
repeat
begin
input "You take:";n
if n < lowlim or n > toplim then
begin
print "Must take between";lowlim;" and";toplim
print "Try again."
ok = false
end
else
ok = true
end
until ok
end = n
function play(player, tokens, taken = integer) = integer
if player = human then
taken = getnum(1,3)
else
begin
if tokens <= 3 then
taken = tokens
else
taken = 4  taken
end
end = taken
procedure report(player = integer)
if player = human then
print "You took the last one. You win. Congratulations!"
else
print "I took the last one, so I win. Sorry about that."
end
var player, tokens, taken = integer
welcome
tokens = maxtokens
taken = 0
player = human
print "You go first."
repeat
begin
show tokens
taken = play(player, tokens, taken)
if player = machine then print "I took:";taken
tokens = tokens  taken
if tokens > 0 then player = 1  player
end
until tokens <= 0
report player
print "Thanks for playing!"
end
 Output:
Welcome to the Game of Nim. We begin with 12 tokens. On each turn, a player may take between 1 and 3 tokens. The player who takes the last token wins. You go first. Available tokens: 12 o o o o o o o o o o o o You take:? 4 Must take between 1 and 3 Try again. You take:? 3 Available tokens: 9 o o o o o o o o o I took: 1 Available tokens: 8 o o o o o o o o You take:? 2 Available tokens: 6 o o o o o o I took: 2 Available tokens: 4 o o o o You take:? 1 Available tokens: 3 o o o I took: 3 I took the last one, so I win. Sorry about that. Thanks for playing!
Tiny BASIC
10 LET H = 12
20 PRINT "There are"
30 PRINT H
40 PRINT "tokens remaining. How many would you like to take?"
50 INPUT T
60 IF T > 3 THEN GOTO 170
70 IF T < 1 THEN GOTO 170
80 LET H = H  T
90 IF H = 0 THEN GOTO 190
100 LET T = 4  T
110 PRINT "I will take"
120 PRINT T
130 PRINT "tokens."
140 LET H = H  T
150 IF H = 0 THEN GOTO 210
160 GOTO 20
170 PRINT "You must take 1, 2, or 3 tokens."
180 GOTO 50
190 PRINT "Congratulations. You got the last token."
200 END
210 PRINT "I got the last token. I win. Better luck next time."
220 END
Tiny Craft Basic
5 cls
10 print "NIM"
20 let h = 12
30 print "There are ", h ," tokens remaining."
40 input "How many would you like to take? ", t
50 if t > 3 then 140
60 if t < 1 then 140
70 let h = h  t
80 if h = 0 then 160
90 let t = 4  t
100 print "I will take ", t ," tokens."
110 let h = h  t
120 if h = 0 then 180
130 goto 30
140 print "You must take between 1 to 3 tokens."
150 goto 40
160 print "Congratulations. You got the last token."
170 goto 190
180 print "I got the last token. I win. Better luck next time."
190 shell "pause"
True BASIC
LET monton = 12
LET llevar = 0
DO WHILE monton > 0
PRINT "Quedan"; monton; "fichas. ¿Cuántas te gustaría tomar";
INPUT llevar
DO WHILE llevar = 0 Or llevar > 3
PRINT "Debes tomar 1, 2, o 3 fichas. ¿Cuántas te gustaría tomar";
INPUT llevar
LOOP
PRINT "Es mi turno, tomaré"; 4llevar; "ficha(s)."
LET monton = monton  4
LOOP
PRINT
PRINT "Obtuve la última ficha. ¡Gané! Mejor suerte la próxima vez."
END
Yabasic
monton = 12
llevar = 0
while monton > 0
print "There are ", monton, " tokens remaining. How many would you like to take? ";
input "" llevar
while llevar = 0 or llevar > 3
input "You must take 1, 2, or 3 tokens. How many would you like to take? " llevar
wend
print "On my turn I will take ", 4  llevar, " token(s)."
monton = monton  4
wend
print "\nI got the last token. I win! Better luck next time."
end
BlooP
Bloop has no input capabilites, so the game is defined as a procedure, called with 3 numbers (since the game will last only 3 rounds anyhow). The procedure can be called with more numbers  extra parameters are ignored in most implementations I have found. Since there is no easy way to get more inputs, any incorrect values are converted to correct ones.
DEFINE PROCEDURE ''DIVIDE'' [A,B]:
BLOCK 0: BEGIN
IF A < B, THEN:
QUIT BLOCK 0;
CELL(0) <= 1;
OUTPUT <= 1;
LOOP AT MOST A TIMES:
BLOCK 2: BEGIN
IF OUTPUT * B = A, THEN:
QUIT BLOCK 0;
OUTPUT <= OUTPUT + 1;
IF OUTPUT * B > A, THEN:
BLOCK 3: BEGIN
OUTPUT <= CELL(0);
QUIT BLOCK 0;
BLOCK 3: END;
CELL(0) <= OUTPUT;
BLOCK 2: END;
BLOCK 0: END.
DEFINE PROCEDURE ''MINUS'' [A,B]:
BLOCK 0: BEGIN
IF A < B, THEN:
QUIT BLOCK 0;
LOOP AT MOST A TIMES:
BLOCK 1: BEGIN
IF OUTPUT + B = A, THEN:
QUIT BLOCK 0;
OUTPUT <= OUTPUT + 1;
BLOCK 1: END;
BLOCK 0: END.
DEFINE PROCEDURE ''MODULUS'' [A,B]:
BLOCK 0: BEGIN
CELL(0) <= DIVIDE[A,B];
OUTPUT <= MINUS[A,CELL(0) * B];
BLOCK 0: END.
DEFINE PROCEDURE ''PLAYER_TURN'' [TOKENS_LEFT, TAKE]:
BLOCK 0: BEGIN
CELL(0) <= TAKE;
IF TAKE > 3, THEN:
BLOCK 1: BEGIN
CELL(0) <= MODULUS [TAKE, 3] + 1;
PRINT ['take must be between 1 and 3. setting take to ', CELL(0), '.'];
BLOCK 1: END;
IF TAKE < 1, THEN:
BLOCK 2: BEGIN
CELL(0) <= 1;
PRINT ['take must be between 1 and 3. setting take to 1.'];
BLOCK 2: END;
OUTPUT <= MINUS [TOKENS_LEFT, CELL(0)];
PRINT ['player takes ', CELL(0), ' tokens.'];
PRINT ['tokens remaining: ', OUTPUT];
PRINT [''];
BLOCK 0: END.
DEFINE PROCEDURE ''COMPUTER_TURN'' [TOKENS_LEFT]:
BLOCK 0: BEGIN
CELL(0) <= MODULUS [TOKENS_LEFT, 4];
OUTPUT <= MINUS [TOKENS_LEFT, CELL(0)];
PRINT ['computer takes ', CELL(0), ' tokens.'];
PRINT ['tokens remaining: ', OUTPUT];
PRINT [''];
BLOCK 0: END.
DEFINE PROCEDURE ''PLAY_GAME'' [FST, SEC, THD]:
BLOCK 0: BEGIN
CELL(0) <= FST;
CELL(1) <= SEC;
CELL(2) <= THD;
OUTPUT <= 12;
LOOP 3 TIMES:
BLOCK 1: BEGIN
OUTPUT <= PLAYER_TURN [OUTPUT, CELL(0)];
CELL(0) <= CELL(1);
CELL(1) <= CELL(2);
OUTPUT <= COMPUTER_TURN [OUTPUT];
BLOCK 1: END;
PRINT ['computer wins!'];
BLOCK 0: END.
PLAY_GAME [1,4,3];
 Output:
Sample game:
> PLAYER TAKES 1 TOKENS. > TOKENS REMAINING: 11 > > COMPUTER TAKES 3 TOKENS. > TOKENS REMAINING: 8 > > TAKE MUST BE BETWEEN 1 AND 3. SETTING TAKE TO 2. > PLAYER TAKES 2 TOKENS. > TOKENS REMAINING: 6 > > COMPUTER TAKES 2 TOKENS. > TOKENS REMAINING: 4 > > PLAYER TAKES 3 TOKENS. > TOKENS REMAINING: 1 > > COMPUTER TAKES 1 TOKENS. > TOKENS REMAINING: 0 > > COMPUTER WINS! => 0
C
#include <stdio.h>
int playerTurn(int numTokens, int take);
int computerTurn(int numTokens);
int main(void)
{
printf("Nim Game\n\n");
int Tokens = 12;
while(Tokens > 0)
{
printf("How many tokens would you like to take?: ");
int uin;
scanf("%i", &uin);
int nextTokens = playerTurn(Tokens, uin);
if (nextTokens == Tokens)
{
continue;
}
Tokens = nextTokens;
Tokens = computerTurn(Tokens);
}
printf("Computer wins.");
return 0;
}
int playerTurn(int numTokens, int take)
{
if (take < 1  take > 3)
{
printf("\nTake must be between 1 and 3.\n\n");
return numTokens;
}
int remainingTokens = numTokens  take;
printf("\nPlayer takes %i tokens.\n", take);
printf("%i tokens remaining.\n\n", remainingTokens);
return remainingTokens;
}
int computerTurn(int numTokens)
{
int take = numTokens % 4;
int remainingTokens = numTokens  take;
printf("Computer takes %u tokens.\n", take);
printf("%i tokens remaining.\n\n", remainingTokens);
return remainingTokens;
}
 Output:
Sample game:
Nim Game How many tokens would you like to take?: 4 Take must be between 1 and 3. How many tokens would you like to take?: 2 Player takes 2 tokens. 10 tokens remaining. Computer takes 2 tokens. 8 tokens remaining. How many tokens would you like to take?: 1 Player takes 1 tokens. 7 tokens remaining. Computer takes 3 tokens. 4 tokens remaining. How many tokens would you like to take?: 3 Player takes 3 tokens. 1 tokens remaining. Computer takes 1 tokens. 0 tokens remaining. Computer wins.
C++
#include <iostream>
#include <limits>
using namespace std;
void showTokens(int tokens) {
cout << "Tokens remaining " << tokens << endl << endl;
}
int main() {
int tokens = 12;
while (true) {
showTokens(tokens);
cout << " How many tokens 1, 2 or 3? ";
int t;
cin >> t;
if (cin.fail()) {
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(), '\n');
cout << endl << "Invalid input, try again." << endl << endl;
} else if (t < 1  t > 3) {
cout << endl << "Must be a number between 1 and 3, try again." << endl << endl;
} else {
int ct = 4  t;
string s = (ct > 1) ? "s" : "";
cout << " Computer takes " << ct << " token" << s << endl << endl;
tokens = 4;
}
if (tokens == 0) {
showTokens(0);
cout << " Computer wins!" << endl;
return 0;
}
}
}
 Output:
Sample game:
Tokens remaining 12 How many tokens 1, 2 or 3? nim Invalid input, try again. Tokens remaining 12 How many tokens 1, 2 or 3? 1 Computer takes 3 tokens Tokens remaining 8 How many tokens 1, 2 or 3? 0 Must be a number between 1 and 3, try again. Tokens remaining 8 How many tokens 1, 2 or 3? 2 Computer takes 2 tokens Tokens remaining 4 How many tokens 1, 2 or 3? 3 Computer takes 1 token Tokens remaining 0 Computer wins!
C#
using System;
namespace nimGame
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("There are twelve tokens.\n" +
"You can take 1, 2, or 3 on your turn.\n" +
"Whoever takes the last token wins.\n");
int tokens = 12;
while (tokens > 0)
{
Console.WriteLine("There are " + tokens + " remaining.");
Console.WriteLine("How many do you take?");
int playertake = Convert.ToInt32(Console.ReadLine());
if (playertake < 1  playertake > 3)
{
Console.WriteLine("1, 2, or 3 only.");
}
else
{
tokens = playertake;
Console.WriteLine("I take " + (4  playertake) + ".");
tokens = (4  playertake);
}
}
Console.WriteLine("I win again.");
Console.ReadLine();
}
}
}
 Output:
Sample game:
There are twelve tokens. You can take 1, 2, or 3 on your turn. Whoever takes the last token wins. There are 12 remaining. How many do you take? 3 I take 1. There are 8 remaining. How many do you take? 1 I take 3. There are 4 remaining. How many do you take? 2 I take 2. I win again.
Clojure
(loop [n 12]
(print (format "%s remain, take how many?\n> " n)) (flush)
(let [v (try (Long. (clojure.string/trim (readline)))
(catch Exception _ 0))]
(if (#{1 2 3} v)
(do (println (format "You took %s, leaving %s, computer takes %s..."
v ( n v) ( 4 v)))
(if (= 4 n)
(println "Computer wins. 😐")
(recur ( n 4))))
(do (println "Please enter 1, 2, or 3...")
(recur n)))))
 Output:
Sample game:
harold@freeside:~/src/cljnim$ rlwrap clj M nim.clj 12 remain, take how many? 3 You took 3, leaving 9, computer takes 1... 8 remain, take how many? 2 You took 2, leaving 6, computer takes 2... 4 remain, take how many? 1 You took 1, leaving 3, computer takes 3... Computer wins. 😐
Common Lisp
(defun pturn (curTokens)
(writestring "How many tokens would you like to take?: ")
(setq ans (read))
(setq tokensRemaining ( curTokens ans))
(format t "You take ~D tokens~%" ans)
(printRemaining tokensRemaining)
tokensRemaining)
(defun cturn (curTokens)
(setq take (mod curTokens 4))
(setq tokensRemaining ( curTokens take))
(format t "Computer takes ~D tokens~%" take)
(printRemaining tokensRemaining)
tokensRemaining)
(defun printRemaining (remaining)
(format t "~D tokens remaining~%~%" remaining))
(format t "LISP Nim~%~%")
(setq tok 12)
(loop
(setq tok (pturn tok))
(setq tok (cturn tok))
(if (<= tok 0)
(return)))
(writestring "Computer wins!")
 Output:
LISP Nim How many tokens would you like to take?: 2 You take 2 tokens 10 tokens remaining Computer takes 2 tokens 8 tokens remaining How many tokens would you like to take?: 1 You take 1 tokens 7 tokens remaining Computer takes 3 tokens 4 tokens remaining How many tokens would you like to take?: 3 You take 3 tokens 1 tokens remaining Computer takes 1 tokens 0 tokens remaining Computer wins!
Crystal
tokens = 12
until tokens <= 0
puts "There are #{tokens} tokens remaining.\nHow many tokens do you take?"
until (input = (gets  "").to_i?) && (1..3).includes? input
puts "Enter an integer between 1 and 3."
end
puts "Player takes #{input} tokens.\nComputer takes #{4input} tokens."
tokens = 4
end
puts "Computer wins."
Dyalect
print("There are twelve tokens.")
print("You can take 1, 2, or 3 on your turn.")
print("Whoever takes the last token wins.\n")
var tokens = 12
while tokens > 0 {
print("There are \(tokens) remaining.")
print("How many do you take?")
var playertake = Integer(readLine())
if playertake < 1  playertake > 3 {
print("1, 2, or 3 only.")
} else {
tokens = playertake
print("I take \(4  playertake).")
tokens = (4  playertake)
}
}
print("I win again.")
EasyLang
[Run it]
token = 12
while token > 0
repeat
print "There are " & token & " tokens remaining."
write "How many would you like to take? (1,2 or 3) "
h = number input
print h
until h >= 1 and h <= 3
.
sleep 1
print "On my turn I will take " & 4  h & " token(s)."
print ""
token = 4
.
print "I got the last token. I win! Better luck next time."
Factor
USING: interpolate io kernel math math.parser sequences ;
IN: rosettacode.nimgame
: getinput (  n )
"Number of tokens to take (1, 2, or 3): " write readln
string>number dup { 1 2 3 } member?
[ drop "Invalid move." print getinput ] unless ;
: .remaining ( n  )
nl [I ~~==[ ${} tokens remaining ]==~~I] nl nl ;
: .choice ( str n  )
dup 1 = "" "s" ? [I ${} took ${} token${}I] nl ;
: (round) (  )
"You" getinput "Computer" 4 pick  [ .choice ] 2bi@ ;
: round ( n  n4 )
dup dup .remaining [ drop (round) 4  round ] unlesszero ;
: nimgame (  ) 12 round drop "Computer wins!" print ;
MAIN: nimgame
 Output:
~~==[ 12 tokens remaining ]==~~ Number of tokens to take (1, 2, or 3): 1 You took 1 token Computer took 3 tokens ~~==[ 8 tokens remaining ]==~~ Number of tokens to take (1, 2, or 3): 3 You took 3 tokens Computer took 1 token ~~==[ 4 tokens remaining ]==~~ Number of tokens to take (1, 2, or 3): 4 Invalid move. Number of tokens to take (1, 2, or 3): 2 You took 2 tokens Computer took 2 tokens ~~==[ 0 tokens remaining ]==~~ Computer wins!
Fermat
heap:=12;
while heap>0 do
!!('There are ',heap,' tokens left. How many do you want to take?');
?take;
while take<1 or take>3 or take>heap do
!!('You cannot take that number. Choose again.');
?take;
od;
!!('On my turn I will take ',4take,' tokens.');
heap:(4);
od;
!!('I got the last token. Better luck next time!');
 Output:
There are 12 tokens left. How many do you want to take?>take := 4 You cannot take that number. Choose again. >take := 3 On my turn I will take 1 tokens. There are 8 tokens left. How many do you want to take? >take := 2 On my turn I will take 2 tokens. There are 4 tokens left. How many do you want to take? >take := 2 On my turn I will take 2 tokens.
I got the last token. Better luck next time!
Go
package main
import (
"bufio"
"fmt"
"os"
"strconv"
)
func showTokens(tokens int) {
fmt.Println("Tokens remaining", tokens, "\n")
}
func main() {
tokens := 12
scanner := bufio.NewScanner(os.Stdin)
for {
showTokens(tokens)
fmt.Print(" How many tokens 1, 2 or 3? ")
scanner.Scan()
if scerr := scanner.Err(); scerr != nil {
fmt.Println("Error reading standard input:", scerr)
return
}
t, err := strconv.Atoi(scanner.Text())
if err != nil  t < 1  t > 3 {
fmt.Println("\nMust be a number between 1 and 3, try again.\n")
} else {
ct := 4  t
s := "s"
if ct == 1 {
s = ""
}
fmt.Print(" Computer takes ", ct, " token", s, "\n\n")
tokens = 4
}
if tokens == 0 {
showTokens(0)
fmt.Println(" Computer wins!")
return
}
}
}
 Output:
Sample game:
Tokens remaining 12 How many tokens 1, 2 or 3? 2 Computer takes 2 tokens Tokens remaining 8 How many tokens 1, 2 or 3? 4 Must be a number between 1 and 3, try again. Tokens remaining 8 How many tokens 1, 2 or 3? 1 Computer takes 3 tokens Tokens remaining 4 How many tokens 1, 2 or 3? 3 Computer takes 1 token Tokens remaining 0 Computer wins!
Haskell
import Data.Char (isDigit, digitToInt)
import System.IO
prompt :: String
prompt = "How many do you take? 1, 2 or 3? "
getPlayerSelection :: IO Int
getPlayerSelection = do
hSetBuffering stdin NoBuffering
c < getChar
putChar '\n'
if isDigit c && digitToInt c <= 3 then
pure (digitToInt c)
else do
putStrLn "Invalid input"
putStr prompt
getPlayerSelection
play :: Int > IO ()
play n = do
putStrLn $ show n ++ token n ++ " remain."
if n == 0 then putStrLn "Computer Wins!"
else do
putStr prompt
playerSelection < getPlayerSelection
let computerSelection
 playerSelection > 4 = playerSelection  4
 otherwise = 4  playerSelection
putStrLn $ "Computer takes " ++ show computerSelection ++ token computerSelection ++ ".\n"
play (n  computerSelection  playerSelection)
where token 1 = " token"
token _ = " tokens"
main :: IO ()
main = play 12
 Output:
12 tokens remain. How many do you take? 1, 2 or 3? 3 Computer takes 1 token. 8 tokens remain. How many do you take? 1, 2 or 3? 2 Computer takes 2 tokens. 4 tokens remain. How many do you take? 1, 2 or 3? 1 Computer takes 3 tokens. 0 tokens remain. Computer Wins!
J
Implementation:
nim=: {{
prompt tokens=: 12
}}
prompt=: {{
echo 'tokens: ',":tokens
if. 1>tokens do.
echo 'game over'
else.
echo 'take 1, 2 or 3 tokens'
end.
}}
take=: {{
assert. y e.1 2 3
assert. 0=#$y
echo 'tokens: ',":tokens=:tokensy
echo 'I take ',(":t=. 4y),' tokens'
prompt tokens=:tokenst
}}
Sample session:
nim''
tokens: 12
take 1, 2 or 3 tokens
take 1
tokens: 11
I take 3 tokens
tokens: 8
take 1, 2 or 3 tokens
take 3
tokens: 5
I take 1 tokens
tokens: 4
take 1, 2 or 3 tokens
take 2
tokens: 2
I take 2 tokens
tokens: 0
game over
Java
import java.util.Scanner;
public class NimGame {
public static void main(String[] args) {
runGame(12);
}
private static void runGame(int tokens) {
System.out.printf("Nim game.%n%n");
Scanner in = new Scanner(System.in);;
do {
boolean humanInputOk = false;
int humanTokens = 0;
while ( ! humanInputOk ) {
System.out.printf("Human takes how many tokens? ");
String input = in.next();
try {
humanTokens = Integer.parseInt(input);
if ( humanTokens >= 1 && humanTokens <= 3 ) {
humanInputOk = true;
}
else {
System.out.printf("Try a number between 1 and 3.%n");
}
}
catch (NumberFormatException e) {
System.out.printf("Invalid input. Try a number between 1 and 3.%n");
}
}
tokens = humanTokens;
System.out.printf("You take %d token%s.%n%d token%s remaining.%n%n", humanTokens, humanTokens > 1 ? "s" : "", tokens, tokens != 1 ? "s" : "");
if ( tokens == 0 ) {
System.out.printf("You win!!.%n%n");
break;
}
int computerTokens = 4  humanTokens;
tokens = computerTokens;
System.out.printf("Computer takes %d token%s.%n%d token%s remaining.%n%n", computerTokens, computerTokens != 1 ? "s" : "", tokens, tokens != 1 ? "s" : "");
if ( tokens == 0 ) {
System.out.printf("Computer wins!!.%n%n");
}
} while (tokens > 0);
in.close();
}
}
 Output:
Sample game:
Nim game. Human takes how many tokens? nim Invalid input. Try a number between 1 and 3. Human takes how many tokens? 0 Try a number between 1 and 3. Human takes how many tokens? 2 You take 2 tokens. 10 tokens remaining. Computer takes 2 tokens. 8 tokens remaining. Human takes how many tokens? 1 You take 1 token. 7 tokens remaining. Computer takes 3 tokens. 4 tokens remaining. Human takes how many tokens? 3 You take 3 tokens. 1 token remaining. Computer takes 1 token. 0 tokens remaining. Computer wins!!.
JavaScript
Browser Version
This is the easy but dirty way  with prompt for input, and console.log for output. The Nim class was structured so that input and output could be customized, for example to use HTML DOM elements for in and out, instead of the terminal.
class Nim {
constructor(tokens, printFun) {
this.startTokens = tokens;
this.tokens = tokens;
this.printFun = printFun;
}
playerTurn(take) {
take = Math.round(take);
if (take < 1  take > 3) {
this.printFun("take must be between 1 and 3.\n")
return false;
}
this.tokens = take;
this.printFun("Player takes " + take + " tokens.");
this.printRemaining()
if (this.tokens === 0) {
this.printFun("Player wins!\n");
}
return true;
}
computerTurn() {
let take = this.tokens % 4;
this.tokens = take;
this.printFun("Computer takes " + take + " tokens.");
this.printRemaining();
if (this.tokens === 0) {
this.printFun("Computer wins.\n");
}
}
printRemaining() {
this.printFun(this.tokens + " tokens remaining.\n");
}
}
let game = new Nim(12, console.log);
while (true) {
if (game.playerTurn(parseInt(prompt("How many tokens would you like to take?")))){
game.computerTurn();
}
if (game.tokens == 0) {
break;
}
}
 Output:
Sample game:
(prompt) How many tokens would you like to take? 2 Player takes 2 tokens. 10 tokens remaining. Computer takes 2 tokens. 8 tokens remaining. (prompt) How many tokens would you like to take? 4 take must be between 1 and 3. (prompt) How many tokens would you like to take? 0 take must be between 1 and 3. (prompt) How many tokens would you like to take? 3 Player takes 3 tokens. 5 tokens remaining. Computer takes 1 tokens. 4 tokens remaining. (prompt) How many tokens would you like to take? 1 Player takes 1 tokens. 3 tokens remaining. Computer takes 3 tokens. 0 tokens remaining. Computer wins.
jq
Also works with gojq, the Go implementation of jq.
def play($tokens):
label $out
 "There are \($tokens) tokens. Take at most \([$tokens,3]min) or enter q to quit.",
( foreach inputs as $in ( {$tokens};
if $in == "q" then break $out
else .in = $in
 if $in  test("^[09]+$") then .in = tonumber else .in = null end
 if .in and .in > 0 and .in < 4
then (4  .in) as $ct
 (if $ct == 1 then "" else "s" end) as $s
 .emit = " Computer takes \($ct) token\($s);"
 .tokens += 4
else .emit = "Please enter a number from 1 to \([3, .tokens]min) inclusive."
end
end;
.emit,
if .tokens == 0
then "\nComputer wins!", break $out
elif .tokens < 0 then "\nCongratulations!", break $out
else "\(.tokens) tokens remain. How many tokens will you take?"
end )) ;
play(12)
$ jq nRr f nimgame.jq There are 12 tokens. Take at most 3 or enter q to quit. 2 Computer takes 2 tokens; 8 tokens remain. How many tokens will you take? 1 Computer takes 3 tokens; 4 tokens remain. How many tokens will you take? 4 Please enter a number from 1 to 3 inclusive. 4 tokens remain. How many tokens will you take? 3 Computer takes 1 token; Computer wins!
Julia
function nimgame()
tcount = 12
takenum = 0
while true
while true
permitted = collect(1:min(3,tcount))
println("$tcount tokens remain.\nHow many do you take ($permitted)? ")
takenum = parse(Int, strip(readline(stdin)))
if takenum in permitted
break
end
end
tcount = 4
println("Computer takes $(4  takenum). There are $tcount tokens left.")
if tcount < 1
println("Computer wins as expected.")
break
end
end
end
nimgame()
 Output:
12 tokens remain. How many do you take ([1, 2, 3])? 3 Computer takes 1. There are 8 tokens left. 8 tokens remain. How many do you take ([1, 2, 3])? 2 Computer takes 2. There are 4 tokens left. 4 tokens remain. How many do you take ([1, 2, 3])? 1 Computer takes 3. There are 0 tokens left. Computer wins as expected.
Kotlin
// Version 1.3.21
fun showTokens(tokens: Int) {
println("Tokens remaining $tokens\n")
}
fun main() {
var tokens = 12
while (true) {
showTokens(tokens)
print(" How many tokens 1, 2 or 3? ")
var t = readLine()!!.toIntOrNull()
if (t == null  t < 1  t > 3) {
println("\nMust be a number between 1 and 3, try again.\n")
} else {
var ct = 4  t
var s = if (ct > 1) "s" else ""
println(" Computer takes $ct token$s\n")
tokens = 4
}
if (tokens == 0) {
showTokens(0)
println(" Computer wins!")
return
}
}
}
 Output:
Sample game:
Tokens remaining 12 How many tokens 1, 2 or 3? 3 Computer takes 1 token Tokens remaining 8 How many tokens 1, 2 or 3? nim Must be a number between 1 and 3, try again. Tokens remaining 8 How many tokens 1, 2 or 3? 2 Computer takes 2 tokens Tokens remaining 4 How many tokens 1, 2 or 3? 1 Computer takes 3 tokens Tokens remaining 0 Computer wins!
Lua
tokens = 12
print("Nim Game\n")
print("Starting with " .. tokens .. " tokens.\n\n")
function printRemaining()
print(tokens .. " tokens remaining.\n")
end
function playerTurn(take)
take = math.floor(take)
if (take < 1 or take > 3) then
print ("\nTake must be between 1 and 3.\n")
return false
end
tokens = tokens  take
print ("\nPlayer takes " .. take .. " tokens.")
printRemaining()
return true
end
function computerTurn()
take = tokens % 4
tokens = tokens  take
print("Computer takes " .. take .. " tokens.")
printRemaining()
end
while (tokens > 0) do
io.write("How many tokens would you like to take?: ")
if playerTurn(io.read("*n")) then
computerTurn()
end
end
print ("Computer wins.")
 Output:
Sample game output:
Nim Game Starting with 12 tokens. How many tokens would you like to take?: 3 Player takes 3 tokens. 9 tokens remaining. Computer takes 1 tokens. 8 tokens remaining. How many tokens would you like to take?: 4 Take must be between 1 and 3. How many tokens would you like to take?: 1 Player takes 1 tokens. 7 tokens remaining. Computer takes 3 tokens. 4 tokens remaining. How many tokens would you like to take?: 2 Player takes 2 tokens. 2 tokens remaining. Computer takes 2 tokens. 0 tokens remaining. Computer wins.
Mathematica/Wolfram Language
n = 12;
While[n > 0,
c = ChoiceDialog["Current amount = " <> ToString[n] <> "\nHow many do you want to pick?", {1 > 1, 2 > 2, 3 > 3}];
n = c;
ChoiceDialog["Current amount = " <> ToString[n] <> "\nComputer takes " <> ToString[4  c]];
n = (4  c);
]
ChoiceDialog["Current amount = " <> ToString[n] <> "\n You lost!"]
MiniScript
tokens = 12
print "Nim Game"
print "Starting with " + tokens + " tokens."
print
printRemaining = function()
print tokens + " tokens remaining."
print
end function
playerTurn = function(take)
take = floor(val(take))
if take < 1 or take > 3 then
print "Take must be between 1 and 3."
return false
end if
globals.tokens = tokens  take
print "Player takes " + take + " tokens."
printRemaining
return true
end function
computerTurn = function()
take = tokens % 4
globals.tokens = tokens  take
print "Computer takes " + take + " tokens."
printRemaining
end function
while tokens > 0
if playerTurn(input("How many tokens would you like to take? ")) then
computerTurn
end if
end while
print "Computer wins."
 Output:
Nim Game Starting with 12 tokens. How many tokens would you like to take? 0 Take must be between 1 and 3. How many tokens would you like to take? 1 Player takes 1 tokens. 11 tokens remaining. Computer takes 3 tokens. 8 tokens remaining. How many tokens would you like to take? 2 Player takes 2 tokens. 6 tokens remaining. Computer takes 2 tokens. 4 tokens remaining. How many tokens would you like to take? 2 Player takes 2 tokens. 2 tokens remaining. Computer takes 2 tokens. 0 tokens remaining. Computer wins.
Nim
import strutils
import terminal
var tokens = 12
styledEcho(styleBright, "Nim in Nim\n")
proc echoTokens() =
styledEcho(styleBright, "Tokens remaining: ", resetStyle, $tokens, "\n")
proc player() =
var take = '0'
styledEcho(styleBright, " Your turn ")
echo "How many tokens will you take?"
while true:
stdout.styledWrite(styleDim, "Take (1–3): ", resetStyle)
take = getch()
stdout.write(take, '\n')
if take in {'1'..'3'}:
tokens = parseInt($take)
break
else:
echo "Please choose a number between 1 and 3."
echoTokens()
proc computer() =
styledEcho(styleBright, " Computer's turn ")
let take = tokens mod 4
tokens = take
styledEcho("Computer took ", styleBright, $take, " ",
if take == 1: "token"
else: "tokens")
echoTokens()
while tokens > 0:
player()
computer()
styledEcho(styleBright, "Computer wins!")
 Output:
 Your turn  How many tokens will you take? Take (1–3): 1 Tokens remaining: 11  Computer's turn  Computer took 3 tokens Tokens remaining: 8  Your turn  How many tokens will you take? Take (1–3): 2 Tokens remaining: 6  Computer's turn  Computer took 2 tokens Tokens remaining: 4  Your turn  How many tokens will you take? Take (1–3): 3 Tokens remaining: 1  Computer's turn  Computer took 1 token Tokens remaining: 0 Computer wins!
OCaml
let rec player_turn () =
print_string "How many tokens would you like to take? ";
let n = read_int_opt () > Option.value ~default:0 in
if n >= 1 && n <= 3 then n
else (
print_endline "Number must be between 1 and 3";
player_turn ())
let computer_turn tokens = tokens mod 4
let plural_suffix = function 1 > ""  _ > "s"
let turn_report prefix taken tokens =
Printf.printf "%s %d token%s.\n%d token%s remaining.\n%!" prefix taken
(plural_suffix taken) tokens (plural_suffix tokens)
let rec play_game tokens =
let player_tokens = player_turn () in
let tokens = tokens  player_tokens in
turn_report "You take" player_tokens tokens;
let computer_tokens = computer_turn tokens in
let tokens = tokens  computer_tokens in
turn_report "Computer takes" computer_tokens tokens;
if tokens = 0 then print_endline "Computer wins!" else play_game tokens
let () = play_game 12
 Output:
How many tokens would you like to take? 3 You take 3 tokens. 9 tokens remaining. Computer takes 1 token. 8 tokens remaining. How many tokens would you like to take? 3 You take 3 tokens. 5 tokens remaining. Computer takes 1 token. 4 tokens remaining. How many tokens would you like to take? 3 You take 3 tokens. 1 token remaining. Computer takes 1 token. 0 tokens remaining. Computer wins!
Pascal
program Nim;
{$mode objfpc}{$H+}
uses
sysutils;
const
maxtokens = 12;
machine = 0;
human = 1;
var
player, tokens, taken : integer;
procedure Welcome;
begin
writeln('The Game of Nim');
writeln;
writeln('This is one of many variants of the classic game of');
writeln('Nim. We start with',maxtokens,' tokens. On each turn a player');
writeln('takes between 1 and 3 tokens. The player who takes');
writeln('the last token wins.');
writeln;
end;
procedure ShowRemaining(n : integer);
begin
writeln('Available tokens: ', n);
end;
function getnum(lowlim, toplim : integer) : integer ;
var
n : integer;
ok : boolean;
begin
repeat
write('You take: ');
readln(n);
if (n < lowlim) or (n > toplim) then
begin
writeln('Must take between ',lowlim,' and ',toplim);
write('Try again: ');
ok := false;
end
else
ok := true;
until ok;
getnum := n;
end;
function PlayTurn(player, taken, tokens : integer) : integer;
begin
if player = human then
taken := getnum(1,3)
else { machine's move this time }
begin
if tokens <= 3 then
taken := tokens { take all if 3 or less remain }
else
taken := 4  taken; { othewise, follow winning strategy }
end;
PlayTurn := taken;
end;
procedure Report(winner : integer);
begin
if winner = human then
writeln('You took the last one, so you win. Congratulations!')
else
writeln('I took the last one, so I win. Sorry about that.');
end;
begin
Welcome;
tokens := maxtokens;
taken := 0;
player := human;
writeln('You go first');
repeat
ShowRemaining(tokens);
taken := PlayTurn(player, taken, tokens);
if player = machine then writeln('I took: ',taken);
tokens := tokens  taken;
if tokens > 0 then player := 1  player;
until tokens <= 0;
report(player);
writeln('Thanks for playing!');
readln;
end.
 Output:
The Game of Nim This is one of many variants of the classic game of Nim. We start with 12 tokens. On each turn a player takes between 1 and 3 tokens. The player who takes the last token wins. You go first Available tokens: 12 You take: 4 Must take between 1 and 3 Try again: 3 Available tokens: 9 I took: 1 Available tokens: 8 You take: 2 Available tokens: 6 I took: 2 Available tokens: 4 You take: 1 Available tokens: 3 I took: 3 I took the last one, so I win. Sorry about that. Thanks for playing!
Pebble
;NIM game example program for x86 DOS
;Compiles with Pebble to com file under 1kb.
program examples\nim
data
int tokens[12]
int take[0]
begin
call intro
label gameloop
echo "There are"
echo [tokens]
echo " tokens remaining."
crlf
echo "How many would you like to take? "
input [take]
if [take] > 3  [take] < 1 then
echo "You must take between 1 to 3 tokens."
endif
if [take] <= 3 & [take] >= 1 then
[tokens] = [tokens]  [take]
if [tokens] = 0 then
bell
echo "Congratulations. You got the last token."
pause
kill
endif
[take] = 4  [take]
echo "I will take"
echo [take]
echo " tokens.
[tokens] = [tokens]  [take]
if [tokens] = 0 then
echo "I got the last token. I win. Better luck next time."
pause
kill
endif
endif
goto gameloop
end
sub intro
cls
echo "NIM game"
crlf
ret
Perl
use strict;
use warnings;
use feature 'say';
my $tokens = 12;
say "$tokens tokens remaining.\n";
while (1) {
print "How many tokens do you want to remove; 1, 2 or 3? : ";
(my $player = <>) =~ s/\s//g;
say "Nice try. $tokens tokens remaining.\n" and next
unless $player =~ /^[123]$/;
$tokens = 4;
say "Computer takes @{[4  $player]}.\n$tokens tokens remaining.\n";
say "Computer wins." and last
if $tokens <= 0;
}
 Output:
12 tokens remaining. How many tokens do you want to remove; 1, 2 or 3? : 3 Computer takes 1. 8 tokens remaining. How many tokens do you want to remove; 1, 2 or 3? : 1 Nice try. 8 tokens remaining. How many tokens do you want to remove; 1, 2 or 3? : 2 Computer takes 2. 4 tokens remaining. How many tokens do you want to remove; 1, 2 or 3? : 1 Computer takes 3. 0 tokens remaining. Computer wins.
Phix
without js  getc integer tokens = 12, player = 0 while true do printf(1,"%2d tokens remaining. ",tokens) if tokens=0 then printf(1,"Computer wins.\n") exit end if printf(1,"How many tokens do you want to remove; 1, 2, or 3?:") while player<1 or player>3 do player=getc(0)'0' end while printf(1,"%d. Computer takes %d.\n",{player,4player}) tokens = 4; player = 0 end while
 Output:
12 tokens remaining. How many tokens do you want to remove; 1, 2, or 3?:1. Computer takes 3. 8 tokens remaining. How many tokens do you want to remove; 1, 2, or 3?:2. Computer takes 2. 4 tokens remaining. How many tokens do you want to remove; 1, 2, or 3?:3. Computer takes 1. 0 tokens remaining. Computer wins.
Pike
int tokens = 12;
void get_tokens(int cur_tokens) {
write("How many tokens would you like to take? ");
int take = (int)Stdio.stdin>gets();
if (take < 1  take > 3) {
write("Number must be between 1 and 3.\n");
get_tokens(cur_tokens);
}
else {
tokens = cur_tokens  take;
write("You take " + (string)take + " tokens\n");
write((string)tokens + " tokens remaing\n\n");
}
}
void comp_turn(int cur_tokens) {
int take = cur_tokens % 4;
tokens = cur_tokens  take;
write("Computer take " + (string)take + " tokens\n");
write((string)tokens + " tokens remaing\n\n");
}
int main() {
write("Pike Nim\n\n");
while(tokens > 0) {
get_tokens(tokens);
comp_turn(tokens);
}
write("Computer wins!\n");
return 0;
}
 Output:
Pike Nim How many tokens would you like to take? 2 You take 2 tokens 10 tokens remaing Computer take 2 tokens 8 tokens remaing How many tokens would you like to take? 6 Number must be between 1 and 3. How many tokens would you like to take? 2 Number must be between 1 and 3. How many tokens would you like to take? 1 You take 1 tokens 7 tokens remaing Computer take 3 tokens 4 tokens remaing How many tokens would you like to take? 3 You take 3 tokens 1 tokens remaing Computer take 1 tokens 0 tokens remaing Computer wins!
Plain English
To run:
Start up.
Play the game of Nim.
Write "The computer wins! Press esc to exit." on the console.
Wait for the escape key.
Shut down.
A piece is a number.
To play the game of Nim:
Put 12 into a piece count.
Loop.
If the piece count is 0, exit.
Write "There are " then the piece count then " pieces remaining." on the console.
Ask the player to take some pieces.
Subtract the pieces from the piece count.
Ask the computer to take some other pieces given the pieces.
Subtract the other pieces from the piece count.
Repeat.
To ask the player to take some pieces:
Write "Would you like to take 1, 2, or 3 pieces? " on the console without advancing.
Read a count from the console.
If the count is not between 1 and 3, repeat.
Format the count and "piece" or "pieces" into a string.
Write "You took " then the string then "." on the console.
Put the count into the pieces.
To ask the computer to take some pieces given some other pieces:
Put 4 minus the other pieces into a count.
Format the count and "piece" or "pieces" into a string.
Write "The computer took " then the string then "." on the console.
Put the count into the pieces.
 Output:
There are 12 pieces remaining. Would you like to take 1, 2, or 3 pieces? apple Would you like to take 1, 2, or 3 pieces? 4 Would you like to take 1, 2, or 3 pieces? 2 You took 2 pieces. The computer took 2 pieces. There are 8 pieces remaining. Would you like to take 1, 2, or 3 pieces? 3 You took 3 pieces. The computer took 1 piece. There are 4 pieces remaining. Would you like to take 1, 2, or 3 pieces? 1 You took 1 piece. The computer took 3 pieces. The computer wins! Press esc to exit.
Prolog
nim : next_turn(12), !.
next_turn(N) :
% Player Turn
format('How many dots would you like to take? '),
read_line_to_codes(user_input, Line),
number_codes(PlayerGuess, Line),
member(PlayerGuess,[1,2,3]),
N1 is N  PlayerGuess,
format('You take ~d dots~n~d dots remaining.~n~n', [PlayerGuess, N1]),
% Computer Turn
CompGuess is 4  PlayerGuess,
N2 is N1  CompGuess,
format('Computer takes ~d dots~n~d dots remaining.~n~n', [CompGuess, N2]),
(
N2 = 0
> format('Computer wins!')
; next_turn(N2)
).
 Output:
? nim. How many dots would you like to take? 2 You take 2 dots 10 dots remaining. Computer takes 2 dots 8 dots remaining. How many dots would you like to take? 3 You take 3 dots 5 dots remaining. Computer takes 1 dots 4 dots remaining. How many dots would you like to take? 1 You take 1 dots 3 dots remaining. Computer takes 3 dots 0 dots remaining. Computer wins! true. ?
Python
Works on Python 3
print("Py Nim\n")
def getTokens(curTokens):
global tokens
print("How many tokens would you like to take? ", end='')
take = int(input())
if (take < 1 or take > 3):
print("Number must be between 1 and 3.\n")
getTokens(curTokens)
return
tokens = curTokens  take
print(f'You take {take} tokens.')
print(f'{tokens} tokens remaining.\n')
def compTurn(curTokens):
global tokens
take = curTokens % 4
tokens = curTokens  take
print (f'Computer takes {take} tokens.')
print (f'{tokens} tokens remaining.\n')
tokens = 12
while (tokens > 0):
getTokens(tokens)
compTurn(tokens)
print("Computer wins!")
 Output:
Py Nim How many tokens would you like to take? 2 You take 2 tokens. 10 tokens remaining. Computer takes 2 tokens. 8 tokens remaining. How many tokens would you like to take? 1 You take 1 tokens. 7 tokens remaining. Computer takes 3 tokens. 4 tokens remaining. How many tokens would you like to take? 3 You take 3 tokens. 1 tokens remaining. Computer takes 1 tokens. 0 tokens remaining. Computer wins!
Quackery
[ $ "Take how many tokens? (13) "
input
trim reverse
trim reverse
$>n
not iff drop again
dup 1 4 within
not iff drop again ] is getmove ( > n )
[ 12
[ say "There are "
dup echo
say " tokens." cr cr
getmove tuck 
4 rot  dup
cr say "Computer takes "
echo
say "." cr cr

dup 0 = until ]
drop
say "Computer wins." cr ] is play ( > )
 Output:
As a dialogue in the Quackery shell.
/O> play ... There are 12 tokens. Take how many tokens? (13) 1 Computer takes 3. There are 8 tokens. Take how many tokens? (13) 2 Computer takes 2. There are 4 tokens. Take how many tokens? (13) 3 Computer takes 1. Computer wins. Stack empty.
R
## Nim game
##
tokens < 12
while(tokens > 0) {
print(paste("Tokens remaining:",tokens))
playertaken < 0
while(playertaken == 0) {
playeropts < c(1:min(c(tokens,3)))
playertaken < menu(playeropts, title = "Your go, how many tokens will you take? ")
tokens < tokens  playertaken
if(tokens == 0) {print("Well done you won, that shouldn't be possible!")}
}
cputaken < 4  playertaken
tokens < tokens  cputaken
print(paste("I take",cputaken,"tokens,",tokens,"remain"))
if(tokens == 0) {print("I win!")}
}
 Output:
[1] "Tokens remaining: 12" Your go, how many tokens will you take? 1: 1 2: 2 3: 3 Selection: 3 [1] "I take 1 tokens, 8 remain" [1] "Tokens remaining: 8" Your go, how many tokens will you take? 1: 1 2: 2 3: 3 Selection: 3 [1] "I take 1 tokens, 4 remain" [1] "Tokens remaining: 4" Your go, how many tokens will you take? 1: 1 2: 2 3: 3 Selection: 3 [1] "I take 1 tokens, 0 remain" [1] "I win!"
Racket
#lang racket
(define (printremaining tokensremaining)
(printf "~a tokens remain.\n" tokensremaining))
(define (readtokens)
(define num (read))
(cond
[(and (natural? num) (< num 4)) num]
[else
(display "Please enter a number between 1 to 3\n")
(readtokens)]))
(define (pturn tokensremaining)
(cond
[(not (zero? tokensremaining))
(printremaining tokensremaining)
(display "Your turn. How many tokens? ")
(define n (readtokens))
(cturn ( tokensremaining n) n)]
[else (display "Computer wins!")]))
(define (cturn tokensremaining ptook)
(cond
[(not (zero? tokensremaining))
(printremaining tokensremaining)
(define ctake ( 4 ptook))
(printf "Computer takes ~a tokens\n" ctake)
(pturn ( tokensremaining ctake))]
[else (display "You win!")]))
(pturn 12)
Raku
(formerly Perl 6)
say my $tokens = 12, " tokens remaining.\n";
loop {
my $player = trim prompt "How many tokens do you want to remove; 1, 2 or 3? : ";
say "Nice try. $tokens tokens remaining.\n" and
next unless $player eq any <1 2 3>;
$tokens = 4;
say "Computer takes {4  $player}.\n$tokens tokens remaining.\n";
say "Computer wins." and last if $tokens <= 0;
}
 Sample output:
12 tokens remaining. How many tokens do you want to remove; 1, 2 or 3? : 3 Computer takes 1. 8 tokens remaining. How many tokens do you want to remove; 1, 2 or 3? : 6 Nice try. 8 tokens remaining. How many tokens do you want to remove; 1, 2 or 3? : G Nice try. 8 tokens remaining. How many tokens do you want to remove; 1, 2 or 3? : 2 Computer takes 2. 4 tokens remaining. How many tokens do you want to remove; 1, 2 or 3? : 1 Computer takes 3. 0 tokens remaining. Computer wins.
Red
Red [
date: 20211024
version: 0.6.4
summary: "Demonstrate the game of Nim in Red for Rosetta Code"
]
taketokens: function [
"Ask the user to take between 1 and 3 tokens."
][
forever [
n: trim ask "Would you like to take 1, 2, or 3 tokens (q to quit)? "
if n = "q" [quit]
n: try [tointeger n]
case [
not integer? n [print "Please enter an integer."]
any [n < 1 n > 3] [print "Please enter a number between 1 and 3."]
true [return n]
]
]
]
tokens: 12
while [tokens > 0][
print ["There are" tokens "tokens remaining."]
n: taketokens
print ["You took" n "tokens."]
tokens: tokens  n
print ["Computer takes" 4  n "tokens."]
tokens: subtract tokens subtract 4 n
]
print "Computer wins!"
 Output:
There are 12 tokens remaining. Would you like to take 1, 2, or 3 tokens (q to quit)? 2 You took 2 tokens. Computer takes 2 tokens. There are 8 tokens remaining. Would you like to take 1, 2, or 3 tokens (q to quit)? 3 You took 3 tokens. Computer takes 1 tokens. There are 4 tokens remaining. Would you like to take 1, 2, or 3 tokens (q to quit)? 4 Please enter a number between 1 and 3. Would you like to take 1, 2, or 3 tokens (q to quit)? apple Please enter an integer. Would you like to take 1, 2, or 3 tokens (q to quit)? 1 You took 1 tokens. Computer takes 3 tokens. Computer wins!
REXX
Programming notes: extra error checking was done with specific informative error messages. Also included was a method of quitting the game. The number of (starting) tokens (the pot) can be specified on the command line, the default is 12.
/*REXX program plays the NIM game with a human opponent; the pot size can be specified. */
parse arg pot _ . 1 __ /*obtain optional argument from the CL.*/
if pot==''  pot=="," then pot= 12 /*Not specified? Then use the default.*/
if _\=='' then do; call ser "Too many arguments entered: " __; exit 13; end
if \isNum(pot) then do; call ser "argument isn't numeric: " pot; exit 13; end
if \isInt(pot) then do; call ser "argument isn't an integer: " pot; exit 13; end
if pot<4 then do; call ser "The pot number is too small: " pot; exit 13; end
if pot>100 then do; call ser "The pot number is too large: " pot; exit 13; end
pad= copies('─', 8) /*literal used as an eyecatcher in msgs*/
pot= pot/1 /*normalize the pot (number). */
t= pot//4
if pot>12 & t\==0 then do; say pad 'The computer takes ' t " token"s(t).
pot= pot  t
end
do forever; call show pot
do until ok; ok= 1; say
say pad "How many tokens do you want to take away (1, 2, or 3) (or QUIT)?"
parse pull t _ . 1 q 1 __; upper q; say
if abbrev('QUIT',q,1) then do; say pad 'Quitting.'; exit 1; end
if t='' then call ser "No arguments entered."
if _\=='' then call ser "Too many arguments entered: " __
if \isNum(t) then call ser "Argument isn't numeric: " t
if \isInt(t) then call ser "Argument isn't an integer: " t
if t<1 then call ser "Argument can't be less than 1: " t
if t>3 then call ser "Argument can't be greater than 3: " t
end /*while*/
t= t/1 /*Normalize the number: 001 2. +3 */
#= max(1, 4t) /*calculate the computer's take─away. */
say pad 'The computer takes ' # " token"s(#).
pot= pot  t  # /*calculate the number of tokens in pot*/
if pot==0 then do; say pad 'No tokens left.' /*No tokens left in the pot? */
say pad "The computer wins!" /*Display a braggart message.*/
exit /*exit this computer program.*/
end
end /*forever*/ /*keep looping until there's a winner. */
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
isNum: return datatype( arg(1), 'N') /*verify that the arg is a number. */
isInt: return datatype( arg(1), 'W') /* " " " " " an integer. */
show: say; say pad "Tokens remaining: " arg(1)' ' pad; say; return
s: if arg(1)==1 then return arg(3); return word(arg(2) 's',1)
ser: if ok then say pad '***error***' arg(1); ok= 0; return
 output when using the default input:
──────── Tokens remaining: 12 ──────── ──────── How many tokens do you want to take away (1, 2, or 3) (or QUIT)? 2 ◄■■■■■■■■■■■ user input ──────── The computer takes 2 tokens. ──────── Tokens remaining: 8 ──────── ──────── How many tokens do you want to take away (1, 2, or 3) (or QUIT)? 3 ◄■■■■■■■■■■■ user input ──────── The computer takes 1 token. ──────── Tokens remaining: 4 ──────── ──────── How many tokens do you want to take away (1, 2, or 3) (or QUIT)? 1 ◄■■■■■■■■■■■ user input ──────── The computer takes 3 tokens. ──────── No tokens left. ──────── The computer wins!
Ring
# Project : CalmoSoft Nim Game
# Date : 16/04/202013:27:07
# Update : 31/03/202119:41:09
# Author : Gal Zsolt (~ CalmoSoft ~)
# Email : <calmosoft@gmail.com>
load "stdlib.ring"
load "guilib.ring"
limit = 4
limit1 = 1
limit2 = 3
limit3 = 5
limit4 = 7
match1 = limit1
match2 = limit2
match3 = limit3
match4 = limit4
move1 = 0
move2 = 0
move3 = 0
move4 = 0
Button1 = list(limit1)
Button2 = list(limit2)
Button3 = list(limit3)
Button4 = list(limit4)
pcMove = 0
width = 60
height = 60
yourScore = 0
pcScore = 0
C_FONTSIZE = 15
C_NIM = "images/nim.jpg"
C_COMPUTER = "images/computer.jpg"
C_PROGRAMMER = "images/programmer.jpg"
app = new qApp
{
win = new qWidget() {
app.StyleFusionBlack()
setWindowTitle('CalmoSoft Nim Game')
setWinIcon(self,"images/nim.jpg")
setWindowFlags(Qt_SplashScreen  Qt_CustomizeWindowHint)
reSize(620,460)
for Col = 1 to limit1
Button1[Col] = new QPushButton(win) {
y = 230+(Col1)*height
setgeometry(y+10,70,width,height)
setSizePolicy(1,1)
seticon(new qicon(new qpixmap(C_NIM)))
setIconSize(new qSize(60,60))
}
next
for Col = 1 to limit2
Button2[Col] = new QPushButton(win) {
y = 170+(Col1)*height
setgeometry(y+10,150,width,height)
setSizePolicy(1,1)
seticon(new qicon(new qpixmap(C_NIM)))
setIconSize(new qSize(60,60))
}
next
for Col = 1 to limit3
Button3[Col] = new QPushButton(win) {
y = 110+(Col1)*height
setgeometry(y+10,230,width,height)
setSizePolicy(1,1)
seticon(new qicon(new qpixmap(C_NIM)))
setIconSize(new qSize(60,60))
}
next
for Col = 1 to limit4
Button4[Col] = new QPushButton(win) {
y = 50+(Col1)*height
setgeometry(y+10,310,width,height)
setSizePolicy(1,1)
seticon(new qicon(new qpixmap(C_NIM)))
setIconSize(new qSize(60,60))
}
next
Row1 = new QPushButton(win) {
setgeometry(500,70,width,height)
setStyleSheet("color:Black;backgroundcolor:Orange")
setSizePolicy(1,1)
setclickevent("deleteRow1()")
settext("Row1") }
Row2 = new QPushButton(win) {
setgeometry(500,150,width,height)
setStyleSheet("color:Black;backgroundcolor:Orange")
setSizePolicy(1,1)
setclickevent("deleteRow2()")
settext("Row2") }
Row3 = new QPushButton(win) {
setgeometry(500,230,width,height)
setStyleSheet("color:Black;backgroundcolor:Orange")
setSizePolicy(1,1)
setclickevent("deleteRow3()")
settext("Row3") }
Row4 = new QPushButton(win) {
setgeometry(500,310,width,height)
setStyleSheet("color:Black;backgroundcolor:Orange")
setSizePolicy(1,1)
setclickevent("deleteRow4()")
settext("Row4") }
labelYourScore = new QLabel(win) { setgeometry(60,20,150,30)
setFont(new qFont("Verdana",C_FONTSIZE,50,0))
settext("Your score: 0") }
labelComputerScore = new QLabel(win) { setgeometry(350,20,150,30)
setFont(new qFont("Verdana",C_FONTSIZE,50,0))
settext("PC score: 0") }
btnNewGame = new QPushButton(win) { setgeometry(60,400,80,30)
setFont(new qFont("Verdana",C_FONTSIZE,50,0))
settext("New")
setclickevent("newGame()") }
btnExit = new QPushButton(win) { setgeometry(400,400,80,30)
setFont(new qFont("Verdana",C_FONTSIZE,50,0))
settext("Exit")
setclickevent("pQuit()") }
btnPcMove = new QPushButton(win) { setgeometry(200,400,140,30)
setFont(new qFont("Verdana",C_FONTSIZE,50,0))
settext("PC move")
setclickevent("pcMove()") }
show()
}
exec()
}
func deleteRow1()
if move2 = 1 or move3 = 1 or move4 = 1
move1 = 0
return
else
move1 = 1
ok
if (match1 > 0) and (move1 = 1)
if pcMove = 1
Button1[match1] { seticon(new qicon(new qpixmap(C_COMPUTER)))
setIconSize(new qSize(55,55))
setenabled(false) }
match1 = match1  1
move1 = 0
ok
if pcMove = 0
Button1[match1] { seticon(new qicon(new qpixmap(C_PROGRAMMER)))
setIconSize(new qSize(55,55))
setenabled(false) }
match1 = match1  1
ok
gameOver()
ok
func deleteRow2()
if move1 = 1 or move3 = 1 or move4 = 1
move2 = 0
return
else
move2 = 1
ok
if match2 > 0 and move2 = 1
if pcMove = 1
Button2[match2] { seticon(new qicon(new qpixmap(C_COMPUTER)))
setIconSize(new qSize(55,55))
setenabled(false) }
match2 = match2  1
move2 = 0
ok
if pcMove = 0
Button2[match2] { seticon(new qicon(new qpixmap(C_PROGRAMMER)))
setIconSize(new qSize(55,55))
setenabled(false) }
match2 = match2  1
ok
gameOver()
ok
func deleteRow3()
if move1 = 1 or move2 = 1 or move4 = 1
move3 = 0
return
else
move3 = 1
ok
if match3 > 0 and move3 = 1
if pcMove = 1
Button3[match3] { seticon(new qicon(new qpixmap(C_COMPUTER)))
setIconSize(new qSize(55,55))
setenabled(false) }
match3 = match3  1
move3 = 0
ok
if pcMove = 0
Button3[match3] { seticon(new qicon(new qpixmap(C_PROGRAMMER)))
setIconSize(new qSize(55,55))
setenabled(false) }
match3 = match3  1
ok
gameOver()
ok
func deleteRow4()
if move1 = 1 or move2 = 1 or move3 = 1
move4 = 0
return
else
move4 = 1
ok
if match4 > 0 and move4 = 1
if pcMove = 1
Button4[match4] { seticon(new qicon(new qpixmap(C_COMPUTER)))
setIconSize(new qSize(55,55))
setenabled(false) }
match4 = match4  1
move4 = 0
ok
if pcMove = 0
Button4[match4] { seticon(new qicon(new qpixmap(C_PROGRAMMER)))
setIconSize(new qSize(55,55))
setenabled(false) }
match4 = match4  1
ok
gameOver()
ok
func pcMove()
move1 = 0
move2 = 0
move3 = 0
move4 = 0
pcMove = 1
for n = 1 to limit
if match1 > 0
rnd = random(match11)+1
for m = 1 to rnd
deleteRow1()
next
exit
ok
if match2 > 0
rnd = random(match21)+1
for m = 1 to rnd
deleteRow2()
next
exit
ok
if match3 > 0
rnd = random(match31)+1
for m = 1 to rnd
deleteRow3()
next
exit
ok
if match4 > 0
rnd = random(match41)+1
for m = 1 to rnd
deleteRow4()
next
exit
ok
next
pcMove = 0
func gameOver()
if (match1 = 0) and (match2 = 0) and (match3 = 0) and (match4 = 0)
if pcMove = 0
pcScore = pcScore + 1
labelComputerScore.settext("PC score: " + string(pcScore))
msgBox("Game Over! You Lost!")
else
yourScore = yourScore + 1
labelYourScore.settext("Your score: " + string(yourScore))
msgBox("Game Over! You Win!")
ok
ok
func newGame()
match1 = limit1
match2 = limit2
match3 = limit3
match4 = limit4
move1 = 0
move2 = 0
move3 = 0
move4 = 0
pcMove = 0
for Col = 1 to limit1
Button1[Col] = new QPushButton(win) {
y = 230+(Col1)*height
setgeometry(y+10,70,width,height)
setSizePolicy(1,1)
seticon(new qicon(new qpixmap(C_NIM)))
setIconSize(new qSize(60,60))
show()
}
next
for Col = 1 to limit2
Button2[Col] = new QPushButton(win) {
y = 170+(Col1)*height
setgeometry(y+10,150,width,height)
setSizePolicy(1,1)
seticon(new qicon(new qpixmap(C_NIM)))
setIconSize(new qSize(60,60))
show()
}
next
for Col = 1 to limit3
Button3[Col] = new QPushButton(win) {
y = 110+(Col1)*height
setgeometry(y+10,230,width,height)
setSizePolicy(1,1)
seticon(new qicon(new qpixmap(C_NIM)))
setIconSize(new qSize(60,60))
show()
}
next
for Col = 1 to limit4
Button4[Col] = new QPushButton(win) {
y = 50+(Col1)*height
setgeometry(y+10,310,width,height)
setSizePolicy(1,1)
seticon(new qicon(new qpixmap(C_NIM)))
setIconSize(new qSize(60,60))
show()
}
next
func msgBox(cText)
mb = new qMessageBox(win) {
setWindowTitle('CalmoSoft Nim Game')
setText(cText)
setstandardbuttons(QMessageBox_OK)
result = exec()
}
func pQuit()
win.close()
app.Quit()
Necessary image files:
Images file
Output:
Nim Game  video
RPL
This task is an opportunity to showcase the use of both persistent variables and local variables, the latter vanishing once the program executed.
The computer has been named "HAL" rather than "Player 2" or "Computer" to keep the message length under 16 characters, which is the width of the HP28 display.
To play, initialize the game by entering the word NUNIM
, then input your moves followed by the word PLNIM
until you will lose. The case for a human win is nevertheless coded to appear as a a fair game.
≪ "Tokens = " tokens →STR + "1..3 PLNIM?" ≫ 'DispN' STO
≪ CLEAR 12 'tokens' STO // emptying the stack and creating a persistent variable DispN ≫ 'NUNIM' STO
≪ → move // creating a local variable, with value = content of stack level 1: ≪ IF { 1 2 3 } move POS THEN "You take " move →STR + 'tokens' move STO // substracting the value of a local variable from a persistent variable directly IF tokens 0 ≤ THEN "You win!" ELSE 4 move  tokens MIN "HAL takes " OVER →STR + 'tokens' ROT STO IF tokens 0 ≤ THEN DROP "HAL wins!" ELSE DispN END END ELSE move →STR " is illegal" + DispN END ≫ ≫ 'PLNIM' STO // 67 words, 4% stack
NUNIM 3 PLNIM 4 PLNIM 2 PLNIM 2 PLNIM
 Output:
15: "Tokens = 12" 14: "1..3 PLNIM?" 13: "You take 3" 12: "HAL takes 1" 11: "Tokens = 8" 10: "1..3 PLNIM?" 9: "4 is illegal" 8: "Tokens = 8" 7: "1..3 PLNIM?" 6: "You take 2" 5: "HAL takes 2" 4: "Tokens = 4" 3: "1..3 PLNIM?" 2: "You take 2" 1: "HAL wins!"
Ruby
[12, 8, 4].each do remaining
puts "There are #{remaining} dots.\nHow many dots would you like to take? "
unless (num=gets.to_i).between?(1, 3)
puts "Please enter one of 1, 2 or 3"
redo
end
puts "You took #{num} dots, leaving #{remainingnum}.\nComputer takes #{4num}.\n\n"
end
puts "Computer took the last and wins."
 Output:
There are 12 dots. How many dots would you like to take? foo Please enter one of 1, 2 or 3 There are 12 dots. How many dots would you like to take? 1 You took 1 dots, leaving 11. Computer takes 3. There are 8 dots. How many dots would you like to take? 3 You took 3 dots, leaving 5. Computer takes 1. There are 4 dots. How many dots would you like to take? 2 You took 2 dots, leaving 2. Computer takes 2. Computer took the last and wins.
Rust
fn main() {
let mut tokens = 12;
println!("Nim game");
println!("Starting with {} tokens.", tokens);
println!("");
loop {
tokens = p_turn(&tokens);
print_remaining(&tokens);
tokens = c_turn(&tokens);
print_remaining(&tokens);
if tokens == 0 {
println!("Computer wins!");
break;
}
}
}
fn p_turn(tokens: &i32) > i32 {
loop { //try until we get a good number
println!("How many tokens would you like to take?");
let mut take = String::new();
io::stdin().read_line(&mut take)
.expect("Sorry, I didn't understand that.");
let take: i32 = match take.trim().parse() {
Ok(num) => num,
Err(_) => {
println!("Invalid input");
println!("");
continue;
}
};
if take > 3  take < 1 {
println!("Take must be between 1 and 3.");
println!("");
continue;
}
return tokens  take;
}
}
fn c_turn(tokens: &i32) > i32 {
let take = tokens % 4;
println!("Computer takes {} tokens.", take);
return tokens  take;
}
fn print_remaining(tokens: &i32) {
println!("{} tokens remaining.", tokens);
println!("");
}
 Output:
sample game:
Nim game Starting with 12 tokens. How many tokens would you like to take? foo Invalid input How many tokens would you like to take? 3 9 tokens remaining. Computer takes 1 tokens. 8 tokens remaining. How many tokens would you like to take? 5 Take must be between 1 and 3. How many tokens would you like to take? 2 6 tokens remaining. Computer takes 2 tokens. 4 tokens remaining. How many tokens would you like to take? 1 3 tokens remaining. Computer takes 3 tokens. 0 tokens remaining. Computer wins!
Scala
var tokens = 12
def playerTurn(curTokens: Int): Unit =
{
val take = readLine("How many tokens would you like to take? ").toInt
if (take < 1  take > 3) {
println("Number must be between 1 and 3.")
playerTurn(curTokens)
}
else {
tokens = curTokens  take
println(s"You take $take tokens. $tokens tokens remaining.\n")
}
}
def compTurn(curTokens: Int): Unit =
{
val take = curTokens % 4
tokens = curTokens  take
println(s"Computer takes $take tokens. $tokens remaining.\n")
}
def main(args: Array[String]): Unit =
{
while (tokens > 0)
{
playerTurn(tokens)
compTurn(tokens)
}
println("Computer wins!")
}
Smalltalk
Object subclass: Nim [
 tokens 
<comment: 'I am a game of nim'>
Nim class >> new [
<category: 'instance creation'>
^(super new) init: 12
]
init: t [
<category: 'instance creation'>
tokens := t.
^self
]
pTurn [
 take 
<category: 'gameplay'>
Transcript nextPutAll: 'How many tokens will you take?: '.
take := (stdin nextLine) asNumber.
((take < 1)  (take > 3))
ifTrue: [Transcript nextPutAll: 'Invalid input';nl;nl. self pTurn]
ifFalse: [tokens := tokens  take]
]
cTurn [
 take 
<category: 'gameplay'>
take := tokens  (4 * (tokens // 4)). "tokens % 4"
Transcript nextPutAll: 'Computer takes '.
take printOn: Transcript.
Transcript nextPutAll: ' tokens';nl.
tokens := tokens  take
]
mainLoop [
<category: 'main loop'>
Transcript nextPutAll: 'Nim game';nl.
Transcript nextPutAll: 'Starting with '.
tokens printOn: Transcript.
Transcript nextPutAll: ' tokens';nl;nl.
1 to: 3 do: [ :n  "The computer always wins on the 3rd turn"
self pTurn.
self printRemaining.
self cTurn.
self printRemaining.
(tokens = 0)
ifTrue:[Transcript nextPutAll: 'Computer wins!';nl. ^0]
]
]
printRemaining [
<category: 'information'>
tokens printOn: Transcript.
Transcript nextPutAll: ' tokens remaining';nl;nl
]
]
g := Nim new.
g mainLoop.
 Output:
sample game:
Nim game Starting with 12 tokens How many tokens will you take?: foo Invalid input How many tokens will you take?: 3 9 tokens remaining Computer takes 1 tokens 8 tokens remaining How many tokens will you take?: 4 Invalid input How many tokens will you take?: 2 6 tokens remaining Computer takes 2 tokens 4 tokens remaining How many tokens will you take?: 1 3 tokens remaining Computer takes 3 tokens 0 tokens remaining Computer wins!
SNOBOL4
&TRIM = 1
&DUMP = 1
OUTPUT(.prompt, 9, 'T', '')
********************************************************************************
* GETCOUNT()  Get the count of tokens to take.
********************************************************************************
define('GETCOUNT()I')
:(GETCOUNT.END)
GETCOUNT OUTPUT = 'Enter a number between 1 and 3, blank line to exit.'
****************************************
* Data input and integrity check loop.
****************************************
GETCOUNT.LOOP PROMPT = '> '
i = trim(INPUT)
* Abort on nil entry.
eq(size(i), 0) :S(EXIT)
* Check range.
integer(i) :F(GETCOUNT.INVALID)
lt(i, 4) :F(GETCOUNT.INVALID)
gt(i, 0) :F(GETCOUNT.INVALID)
* It all checked out.
GETCOUNT = i :(RETURN)
****************************************
* An invalid entry was caught.
****************************************
GETCOUNT.INVALID OUTPUT = 'Invalid number.' :(GETCOUNT.LOOP)
GETCOUNT.END
********************************************************************************
* MAINLINE CODE
********************************************************************************
MAIN OUTPUT =
OUTPUT = 'The mysterious game of Nim!'
OUTPUT = 'Whoever takes the last token of twelve wins.'
tokens = 12
****************************************
* MAIN LOOP
****************************************
MAIN.LOOP OUTPUT =
OUTPUT = 'There are ' tokens ' tokens remaining. How many do you want to take?'
********************
* Player turn.
********************
MAIN.P ptake = getcount()
tokens = tokens  ptake
OUTPUT = 'You selected ' ptake ' tokens leaving ' tokens '.'
lt(tokens, 0) :S(ERROR)
gt(tokens, 12) :S(ERROR)
eq(tokens, 0) :S(MAIN.PWIN)
********************
* Computer turn.
********************
MAIN.C ctake = 4  ptake
tokens = tokens  ctake
OUTPUT = 'Computer selects ' ctake ' tokens leaving ' tokens '.'
lt(tokens, 0) :S(ERROR)
gt(tokens, 12) :S(ERROR)
eq(tokens, 0) :S(MAIN.CWIN)
:(MAIN.LOOP)
****************************************
* Player win is impossible. Joke code.
****************************************
MAIN.PWIN OUTPUT = 'Player wins. This is impossible. You must have cheated.'
OUTPUT = 'Formatting hard drive...' :(ERROR)
****************************************
* Computer win is inevitable.
****************************************
MAIN.CWIN OUTPUT = 'Computer wins.' :(EXIT)
********************************************************************************
* On a routine exit we turn off the variable dump.
* If we exit through an error (like branching to a nonexistent label 'ERROR')
* then this code doesn't happen and variables get dumped and the line of the
* failed check getting printed.
********************************************************************************
EXIT OUTPUT = 'Bye!'
&DUMP = 0
END
The mysterious game of Nim! Whoever takes the last token of twelve wins. There are 12 tokens remaining. How many do you want to take? Enter a number between 1 and 3, blank line to exit. > 4 Invalid number. > 0 Invalid number. > test Invalid number. > 3 You selected 3 tokens leaving 9. Computer selects 1 tokens leaving 8. There are 8 tokens remaining. How many do you want to take? Enter a number between 1 and 3, blank line to exit. > 2 You selected 2 tokens leaving 6. Computer selects 2 tokens leaving 4. There are 4 tokens remaining. How many do you want to take? Enter a number between 1 and 3, blank line to exit. > 1 You selected 1 tokens leaving 3. Computer selects 3 tokens leaving 0. Computer wins. Bye!
Swift
var tokens = 12
while tokens != 0 {
print("Tokens remaining: \(tokens)\nPlease enter a number between 1 and 3: ", terminator: "")
guard let input = readLine(), let n = Int(input), n >= 1 && n <= 3 else {
fatalError("Invalid input")
}
tokens = n
if tokens == 0 {
print("You win!")
break
}
print("I'll remove \(4  n) tokens.")
tokens = 4  n
if tokens == 0 {
print("I win!")
}
print()
}
 Output:
Tokens remaining: 12 Please enter a number between 1 and 3: 3 I'll remove 1 tokens. Tokens remaining: 8 Please enter a number between 1 and 3: 2 I'll remove 2 tokens. Tokens remaining: 4 Please enter a number between 1 and 3: 3 I'll remove 1 tokens. I win!
V (Vlang)
import os { input }
fn show_tokens(tokens int) {
println('Tokens remaining $tokens\n')
}
fn main() {
mut tokens := 12
for {
show_tokens(tokens)
t := input(' How many tokens 1, 2, or 3? ').int()
if t !in [1, 2, 3] {
println('\nMust be a number between 1 and 3, try again.\n')
} else {
ct := 4  t
mut s := 's'
if ct == 1 {
s = ''
}
println(' Computer takes $ct token$s \n')
tokens = 4
}
if tokens == 0 {
show_tokens(0)
println(' Computer wins!')
return
}
}
}
 Output:
Sample game:
Tokens remaining 12 How many tokens 1, 2 or 3? 2 Computer takes 2 tokens Tokens remaining 8 How many tokens 1, 2 or 3? 4 Must be an integer between 1 and 3, try again. Tokens remaining 8 How many tokens 1, 2 or 3? 1 Computer takes 3 tokens Tokens remaining 4 How many tokens 1, 2 or 3? 3 Computer takes 1 token Tokens remaining 0 Computer wins!
Wren
import "io" for Stdin, Stdout
var showTokens = Fn.new { tokens System.print("Tokens remaining %(tokens)\n") }
var tokens = 12
while (true) {
showTokens.call(tokens)
System.write(" How many tokens 1, 2 or 3? ")
Stdout.flush()
var t = Num.fromString(Stdin.readLine())
if (t.type != Num  !t.isInteger  t < 1  t > 3) {
System.print("\nMust be an integer between 1 and 3, try again.\n")
} else {
var ct = 4  t
var s = (ct != 1) ? "s" : ""
System.write(" Computer takes %(ct) token%(s)\n\n")
tokens = tokens  4
}
if (tokens == 0) {
showTokens.call(0)
System.print(" Computer wins!")
break
}
}
 Output:
Sample game:
Tokens remaining 12 How many tokens 1, 2 or 3? 2 Computer takes 2 tokens Tokens remaining 8 How many tokens 1, 2 or 3? 4 Must be an integer between 1 and 3, try again. Tokens remaining 8 How many tokens 1, 2 or 3? 1 Computer takes 3 tokens Tokens remaining 4 How many tokens 1, 2 or 3? 3 Computer takes 1 token Tokens remaining 0 Computer wins!
XPL0
func ShowTokens(Tokens);
int Tokens;
[Text(0, "Tokens remaining: ");
IntOut(0, Tokens);
CrLf(0); CrLf(0);
];
int Tokens, T, CT;
[Tokens:= 12;
loop [ShowTokens(Tokens);
Text(0, " How many Tokens (1, 2 or 3)? ");
T:= IntIn(0);
if T < 1 or T > 3 then
Text(0, "^m^jMust be a number between 1 and 3. Try again.^m^j^m^j")
else [CT:= 4  T;
Text(0, " Computer takes ");
IntOut(0, CT);
Text(0, " token");
if CT # 1 then ChOut(0, ^s);
Text(0, ".^m^j^m^j");
Tokens:= Tokens  4;
];
if Tokens = 0 then
[ShowTokens(0);
Text(0, " Computer wins!^m^j");
return;
];
];
]
 Output:
Tokens remaining: 12 How many Tokens (1, 2 or 3)? 2 Computer takes 2 tokens. Tokens remaining: 8 How many Tokens (1, 2 or 3)? 4 Must be a number between 1 and 3. Try again. Tokens remaining: 8 How many Tokens (1, 2 or 3)? 1 Computer takes 3 tokens. Tokens remaining: 4 How many Tokens (1, 2 or 3)? 3 Computer takes 1 token. Tokens remaining: 0 Computer wins!
Z80 Assembly
Use the /S8 switch on the ZSM4 assembler for 8 significant characters for labels and names
This assembles to 99 bytes of instructions plus 98 bytes of static data for the texts and buffer, accounting for a total of 197 bytes. Not sure whether the 8080 and 8086 versions counted only instruction size or total program size, but the Z80 provides some powerful looping instructions that help to reduce program size.
Please note that I did not bother with conversion from input characters to integers and using comparisons to validate them, nor did I use arithmetic to calculate the computer's move. Instead, I used fixed strings and the cpdr instruction to look up the user's input as well as the computer's response. The CP/M BDOS call ensures that the user can enter a single character only.
;
; Nim game using Z80 assembly language
;
; Runs under CP/M 3.1 on YAZEAG2.51.2 Z80 emulator
; Assembled with zsm4 on same emulator/OS, uses macro capabilities of said assembler
; Created with vim under Windows
;
; 20230428 Xorph
;
;
; Useful definitions
;
bdos equ 05h ; Call to CP/M BDOS function
readstr equ 0ah ; Read string from console
wrtstr equ 09h ; Write string to console
cr equ 0dh ; ASCII control characters
lf equ 0ah
buflen equ 01h ; Length of input buffer
maxtok equ 12 ; Starting number of tokens
;
; Macro for BDOS calls
;
readln macro buf ; Read a line from input
push bc
ld c,readstr
ld de,buf
call bdos
pop bc
endm
;
; =====================
; Start of main program
; =====================
;
cseg
ld de,nim ; Print title and initialize
call print
ld c,maxtok ; Register c keeps track of remaining tokens
loop:
ld de,tokens ; Print the remaining tokens
call print
ld b,c ; Use b for loop to print remaining tokens
printtk:
ld de,token
call print
djnz printtk
ld de,prompt ; Prompt user for input
call print
readln inputbuf
ld a,(bufcont) ; Now check input for validity and compute response
ld hl,validinp+2 ; Start from end of valid string, so bc gets set to numeric equivalent
push bc ; Save token counter, use bc for cpdr
ld bc,3
cpdr ; Use automatic search function
jr nz,printerr ; If input character not found, print error
ld hl,mymoves ; Get character for response into a
add hl,bc ; bc contains index into check string as well as response string
pop bc
ld a,(hl)
ld (outbuf),a ; Put it in output buffer
ld de,response ; Print the computer's move
call print
ld a,c ; Subtract 4 tokens from counter
sub 4
ld c,a
jr nz,loop ; If not finished, repeat
ld de,lose ; Otherwise, player lost
call print
ret ; Return to CP/M
printerr: ; Print error message and try again
pop bc
ld de,wronginp
call print
jp loop
print: ; Use subroutine instead of macro for smaller code
push bc
ld c,wrtstr
call bdos
pop bc
ret
;
; ===================
; End of main program
; ===================
;
;
; ================
; Data definitions
; ================
;
dseg
inputbuf: ; Input buffer
defb buflen ; Maximum possible length
defb 00h ; Returned length of actual input
bufcont:
defs buflen ; Actual input area
nim:
defb 'Nim$' ; Dialog texts
prompt:
defb cr,lf,'How many will you take (13)? $'
response:
defb cr,lf,'I take ' ; No $ here! Saves one print command
outbuf:
defb ' $' ; For printing response
tokens:
defb cr,lf,cr,lf,'Tokens: $'
token:
defb '$'
lose:
defb cr,lf,'You lose!$'
wronginp:
defb cr,lf,'Wrong input$'
validinp:
defb '123' ; Valid input
mymoves:
defb '321' ; Computer's response
 Output:
E>nim Nim Tokens:  How many will you take (13)? 2 I take 2 Tokens:  How many will you take (13)? 4 Wrong input Tokens:  How many will you take (13)? 3 I take 1 Tokens:  How many will you take (13)? 1 I take 3 You lose! E>
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