# War card game

**War card game**

You are encouraged to solve this task according to the task description, using any language you may know.

War Card Game

Simulate the card game War. Use the Bicycle playing card manufacturer's rules. Show a game as played. User input is optional.

References:

- Bicycle card company: War game site

- Wikipedia: War (card game)

Related tasks:

## 11l

```
UInt32 seed = 0
F nonrandom(n)
:seed = (1664525 * :seed + 1013904223) [&] FFFF'FFFF
R Int(:seed >> 16) % n
F nonrandom_shuffle(&x)
L(i) (x.len - 1 .< 0).step(-1)
V j = nonrandom(i + 1)
swap(&x[i], &x[j])
V SUITS = [‘♣’, ‘♦’, ‘♥’, ‘♠’]
V FACES = [‘2’, ‘3’, ‘4’, ‘5’, ‘6’, ‘7’, ‘8’, ‘9’, ‘10’, ‘J’, ‘Q’, ‘K’, ‘A’]
V DECK = multiloop(FACES, SUITS, (f, s) -> f‘’s)
V CARD_TO_RANK = Dict((0 .< DECK.len).map(i -> (:DECK[i], (i + 3) I/ 4)))
T WarCardGame
[String] deck1, deck2, pending
F ()
V deck = copy(:DECK)
nonrandom_shuffle(&deck)
.deck1 = deck[0.<26]
.deck2 = deck[26..]
F gameover()
‘ game over who won message ’
I .deck2.empty
I .deck1.empty
print("\nGame ends as a tie.")
E
print("\nPlayer 1 wins the game.")
E
print("\nPlayer 2 wins the game.")
R 0B
F turn()
‘ one turn, may recurse on tie ’
I .deck1.empty | .deck2.empty
R .gameover()
V card1 = .deck1.pop(0)
V card2 = .deck2.pop(0)
V (rank1, rank2) = (:CARD_TO_RANK[card1], :CARD_TO_RANK[card2])
print(‘#<10#<10’.format(card1, card2), end' ‘’)
I rank1 > rank2
print(‘Player 1 takes the cards.’)
.deck1.extend([card1, card2])
.deck1.extend(.pending)
.pending.clear()
E I rank1 < rank2
print(‘Player 2 takes the cards.’)
.deck2.extend([card2, card1])
.deck2.extend(.pending)
.pending.clear()
E
print(‘Tie!’)
I .deck1.empty | .deck2.empty
R .gameover()
V card3 = .deck1.pop(0)
V card4 = .deck2.pop(0)
.pending.extend([card1, card2, card3, card4])
print(‘#<10#<10’.format(‘?’, ‘?’)‘Cards are face down.’)
R .turn()
R 1B
V WG = WarCardGame()
L WG.turn()
L.continue
```

- Output:

7♦ 10♦ Player 2 takes the cards. 10♥ K♥ Player 2 takes the cards. 7♥ 6♣ Player 1 takes the cards. 8♦ 5♥ Player 1 takes the cards. 4♥ 3♥ Player 1 takes the cards. A♣ 9♣ Player 1 takes the cards. 6♠ 4♦ Player 1 takes the cards. K♣ 3♠ Player 1 takes the cards. A♠ 7♣ Player 1 takes the cards. 10♠ J♥ Player 2 takes the cards. J♦ Q♣ Tie! ? ? Cards are face down. 6♦ Q♠ Player 2 takes the cards. ... 5♠ 4♦ Player 1 takes the cards. Q♣ K♥ Player 2 takes the cards. 10♣ 9♠ Tie! ? ? Cards are face down. 8♥ 10♥ Player 2 takes the cards. 8♣ J♣ Player 2 takes the cards. 5♦ 5♣ Player 1 takes the cards. 5♠ 3♥ Player 1 takes the cards. 4♦ 3♣ Player 1 takes the cards. 5♦ 7♦ Player 2 takes the cards. 5♣ 7♥ Player 2 takes the cards. 5♠ 6♥ Player 2 takes the cards. 3♥ A♥ Player 2 takes the cards. 4♦ 8♠ Player 2 takes the cards. 3♣ 4♠ Player 2 takes the cards. Player 2 wins the game.

## Applesoft BASIC

- The Bicycle rules are set up by default.
- When the winning player picks up cards, the cards are randomized when added to the bottom of the player's deck. see Raku for details.
- Other variations can be played by passing different parameters.

```
100 R = RND (0): REM SEED
110 W = 1: REM BICYCLE RULE: ONLY ONE EXTRA CARD GIVEN UP IN WAR
120 P = 2: REM BICYCLE RULE: ONLY TWO PLAYERS
130 D = 1: REM BICYCLE RULE: ONLY ONE DECK OF CARDS
140 DIM D$(P),C$(P),G(P),L(P)
150 SUIT$ = "CDHS"
160 FACE$ = "23456789TJQKA"
170 M = LEN (SUIT$)
180 FOR I = 1 TO D: FOR S = 1 TO M: FOR F = 1 TO LEN (FACE$):P$ = P$ + CHR$ ((F - 1) * M + (S - 1)): NEXT F,S,I
190 TEXT : HOME : POKE 34,12
REM DEAL TO PLAYERS
200 GOSUB 700"SHUFFLE
210 E = INT (N / P)
220 FOR I = 1 TO P
230 D$(I) = MID$ (P$,(I - 1) * E + 1,E)
240 NEXT
250 P$ = MID$ (P$,(I - 1) * E + 1): REM WINNER OF THE FIRST PLAY KEEPS THESE REMAINING CARDS
260 P$ = "": REM REMOVE REMAINING CARDS FROM THE GAME
REM PLAY
300 FOR T = 0 TO 1E38
310 GOSUB 400"TURN
320 IF Q = 0 THEN NEXT T
330 PRINT " IN "T" TURNS": TEXT : VTAB 11: PRINT : CALL - 868: PRINT "...": VTAB 23
340 END
REM TURN
400 PRINT : GOSUB 900"IS GAME OVER?
410 IF Q THEN RETURN
420 U = 0: REM UTMOST CARD
430 C = 0: REM COUNT THE PLAYERS WITH THE UTMOST CARD
440 FOR I = 1 TO P
450 C$(I) = "" : IF NOT L(I) THEN C$(I) = MID$ (D$(I),1,1)
460 IF LEN (C$(I)) THEN GOSUB 800"DRAW CARD
470 NEXT I
480 IF C = 1 GOTO 600"WINNER TAKE CARDS
490 FOR I = 1 TO P:L(I) = G(I) < > U: NEXT I
500 PRINT "WAR! ";
510 GOSUB 900"IS GAME OVER?
520 IF Q THEN RETURN
530 C = 0
540 FOR I = 1 TO P:P$ = P$ + C$(I): NEXT I
550 FOR I = 1 TO P
REM DOES NOT APPLY TO 2 PLAYER GAMES (BICYCLE RULE): Y MEANS IGNORE THE RULE THAT ONLY THE WINNERS PLACE CARD(S) FACE DOWN
560 IF Y OR NOT L(I) THEN FOR J = 1 TO W:C$ = MID$ (D$(I),1,1) :C = C + LEN(C$) : P$ = P$ + C$ :D$(I) = MID$ (D$(I),2): NEXT J
570 NEXT I
580 PRINT C" CARDS PLACED FACE DOWN.";
590 RETURN
REM WINNER TAKE CARDS
600 FOR I = 1 TO P
610 L(I) = 0
620 P$ = P$ + C$(I)
630 NEXT I
640 PRINT "PLAYER "A" TAKES "LEN(P$);
650 IF NOT Z THEN GOSUB 710"SHUFFLE
660 D$(A) = D$(A) + P$
670 P$ = ""
680 RETURN
REM SHUFFLE
700 PRINT "SHUFFLING ";
710 N = LEN (P$)
720 FOR I = 1 TO N
730 IF I - INT (I / 4) * 4 = 1 THEN PRINT ".";
740 R = INT ( RND (1) * N + 1)
750 R$ = MID$ (P$,R,1) : C$ = MID$ (P$,I,1)
760 P$ = MID$ (P$,1,I - 1) + R$ + MID$ (P$,I + 1)
770 P$ = MID$ (P$,1,R - 1) + C$ + MID$ (P$,R + 1)
780 NEXT
790 RETURN
REM DRAW CARD
800 G = ASC (C$(I))
810 G(I) = INT (G / M) + 1
820 PRINT MID$ (FACE$,G(I),1) MID$ (SUIT$,G - (G(I) - 1) * M + 1,1)" ";
830 D$(I) = MID$ (D$(I),2)
840 C = C + (G(I) = U)
850 IF G(I) > U THEN U = G(I):C = 1:A = I
860 RETURN
REM IS GAME OVER?
900 C = 0
910 FOR I = 1 TO P
920 IF LEN (D$(I)) THEN A = I:C = C + 1
930 NEXT I
940 IF C > 1 THEN RETURN
REM GAME OVER - WHO WON MESSAGE
950 Q = 1
960 IF C THEN PRINT "PLAYER "A" WINS THE GAME";: RETURN
970 PRINT "GAME ENDS AS A TIE";: RETURN
```

```
CLEAR : R = RND ( - 58) : GOTO 110
```

- Output:

SHUFFLING ............. JD 9H PLAYER 1 TAKES 2. 4C 5C PLAYER 2 TAKES 2. 2D 8C PLAYER 2 TAKES 2. TH AS PLAYER 2 TAKES 2. 7D QS PLAYER 2 TAKES 2. 4S 8H PLAYER 2 TAKES 2. AD 7C PLAYER 1 TAKES 2. JS 2S PLAYER 1 TAKES 2. 3C 3S WAR! 2 CARDS PLACED FACE DOWN. TD KH PLAYER 2 TAKES 6.. ... 8D 2D PLAYER 1 TAKES 2. TD 7C PLAYER 1 TAKES 2. 7S 6C PLAYER 1 TAKES 2. 9H 8H PLAYER 1 TAKES 2. 3D 8C PLAYER 2 TAKES 2. AD 3C PLAYER 1 TAKES 2. 4H 4C WAR! 2 CARDS PLACED FACE DOWN. 7D 7H WAR! 2 CARDS PLACED FACE DOWN. JH 3D PLAYER 1 TAKES 10... 9D 8C PLAYER 1 TAKES 2. PLAYER 1 WINS THE GAME IN 432 TURNS

## AutoHotkey

```
suits := ["♠", "♦", "♥", "♣"]
faces := [2,3,4,5,6,7,8,9,10,"J","Q","K","A"]
deck := [], p1 := [], p2 := []
for i, s in suits
for j, v in faces
deck.Push(v s)
deck := shuffle(deck)
deal := deal(deck, p1, p2)
p1 := deal.1, p2 := deal.2
for i, v in p2
{
if InStr(v, "A")
p2[i] := p1[i], p1[i] := v
if InStr(v, "K")
p2[i] := p1[i], p1[i] := v
if InStr(v, "Q")
p2[i] := p1[i], p1[i] := v
if InStr(v, "J")
p2[i] := p1[i], p1[i] := v
}
MsgBox % war(p1, p2)
return
war(p1, p2){
J:=11, Q:=11, K:=11, A:=12, stack := [], cntr := 0
output := "------------------------------------------"
. "`nRound# Deal Winner P1 P1"
. "`n------------------------------------------"
. "`nround0 26 26"
while (p1.Count() && p2.Count()) {
cntr++
stack.Push(c1:=p1.RemoveAt(1)), stack.Push(c2:=p2.RemoveAt(1))
r1:=SubStr(c1,1,-1) ,r2:=SubStr(c2,1,-1)
v1:=r1<11?r1:%r1% ,v2:=r2<11?r2:%r2%
output .= "`nround# " cntr "`t" SubStr(c1 " n", 1, 4) "vs " SubStr(c2 " ", 1, 4)
if (v1 > v2){
loop % stack.Count()
p1.Push(stack.RemoveAt(1))
output .= "`t`tP1 wins"
}
else if (v1 < v2){
loop % stack.Count()
p2.Push(stack.RemoveAt(1))
output .= "`t`tP2 wins"
}
if (v1 = v2){
output .= "`t`t**WAR**`t" P1.Count() "`t" P2.Count()
stack.Push(c1:=p1.RemoveAt(1)), stack.Push(c2:=p2.RemoveAt(1))
if !(p1.Count() && p2.Count())
break
output .= "`nround# " ++cntr "`t(" SubStr(c1 " ", 1, 3) ") - (" SubStr(c2 " ", 1, 3) ")"
output .= "`tFace Dn"
}
output .= "`t" P1.Count() "`t" P2.Count()
if !Mod(cntr, 20)
{
MsgBox % output
output := ""
}
}
output .= "`n" (P1.Count() ? "P1 Wins" : "P2 Wins")
output := StrReplace(output, " )", ") ")
output := StrReplace(output, " -", " -")
return output
```

- Output:

------------------------------------------ Round# Deal Winner P1 P1 ------------------------------------------ round0 26 26 round# 1 J♣ vs 3♠ P1 wins 27 25 round# 2 3♣ vs 10♦ P2 wins 26 26 round# 3 Q♣ vs 8♠ P1 wins 27 25 round# 4 A♦ vs 7♠ P1 wins 28 24 round# 5 J♥ vs 3♦ P1 wins 29 23 round# 6 8♦ vs 4♦ P1 wins 30 22 round# 7 4♥ vs 6♦ P2 wins 29 23 round# 8 7♥ vs 4♠ P1 wins 30 22 round# 9 A♠ vs 7♣ P1 wins 31 21 round# 10 K♣ vs 10♠ P1 wins 32 20 round# 11 4♣ vs 8♥ P2 wins 31 21 round# 12 6♠ vs 6♥ **WAR** 30 20 round# 13 (A♥) - (9♠) Face Dn 29 19 round# 14 5♣ vs 2♥ P1 wins 34 18 round# 15 A♣ vs 8♣ P1 wins 35 17 round# 16 J♦ vs 6♣ P1 wins 36 16 round# 17 Q♥ vs 9♣ P1 wins 37 15 round# 18 10♥ vs 5♠ P1 wins 38 14 round# 19 K♥ vs K♠ **WAR** 37 13 round# 20 (Q♠) - (9♥) Face Dn 36 12 round# 21 K♦ vs 3♥ P1 wins 41 11 round# 22 J♠ vs 2♦ P1 wins 42 10 round# 23 5♥ vs 5♦ **WAR** 41 9 round# 24 (2♣) - (7♦) Face Dn 40 8 round# 25 Q♦ vs 10♣ P1 wins 45 7 round# 26 9♦ vs 2♠ P1 wins 46 6 round# 27 J♣ vs 3♣ P1 wins 47 5 round# 28 3♠ vs 10♦ P2 wins 46 6 round# 29 Q♣ vs 4♥ P1 wins 47 5 round# 30 8♠ vs 6♦ P1 wins 48 4 round# 31 A♦ vs 4♣ P1 wins 49 3 round# 32 7♠ vs 8♥ P2 wins 48 4 round# 33 J♥ vs 3♠ P1 wins 49 3 round# 34 3♦ vs 10♦ P2 wins 48 4 round# 35 8♦ vs 7♠ P1 wins 49 3 round# 36 4♦ vs 8♥ P2 wins 48 4 round# 37 7♥ vs 3♦ P1 wins 49 3 round# 38 4♠ vs 10♦ P2 wins 48 4 round# 39 A♠ vs 4♦ P1 wins 49 3 round# 40 7♣ vs 8♥ P2 wins 48 4 round# 41 K♣ vs 4♠ P1 wins 49 3 round# 42 10♠ vs 10♦ **WAR** 48 2 round# 43 (6♠) - (7♣) Face Dn 47 1 round# 44 6♥ vs 8♥ P2 wins 46 6 round# 45 A♥ vs 10♠ P1 wins 47 5 round# 46 9♠ vs 10♦ P2 wins 46 6 round# 47 5♣ vs 6♠ P2 wins 45 7 round# 48 2♥ vs 7♣ P2 wins 44 8 round# 49 A♣ vs 6♥ P1 wins 45 7 round# 50 8♣ vs 8♥ **WAR** 44 6 round# 51 (J♦) - (9♠) Face Dn 43 5 round# 52 6♣ vs 10♦ P2 wins 42 10 round# 53 Q♥ vs 5♣ P1 wins 43 9 round# 54 9♣ vs 6♠ P1 wins 44 8 round# 55 10♥ vs 2♥ P1 wins 45 7 round# 56 5♠ vs 7♣ P2 wins 44 8 round# 57 K♥ vs 8♣ P1 wins 45 7 round# 58 K♠ vs 8♥ P1 wins 46 6 round# 59 Q♠ vs J♦ **WAR** 45 5 round# 60 (9♥) - (9♠) Face Dn 44 4 round# 61 K♦ vs 6♣ P1 wins 49 3 round# 62 3♥ vs 10♦ P2 wins 48 4 round# 63 J♠ vs 5♠ P1 wins 49 3 round# 64 2♦ vs 7♣ P2 wins 48 4 round# 65 5♥ vs 3♥ P1 wins 49 3 round# 66 5♦ vs 10♦ P2 wins 48 4 round# 67 2♣ vs 2♦ **WAR** 47 3 round# 68 (7♦) - (7♣) Face Dn 46 2 round# 69 Q♦ vs 5♦ P1 wins 51 1 round# 70 10♣ vs 10♦ **WAR** 50 0 P1 Wins

## C++

```
#include <iostream>
#include <vector>
#include <algorithm>
class war_game {
public:
war_game() {
for ( char suit : SUITS ) {
for ( char pip : PIPS ) {
deck.emplace_back(card(suit, pip));
}
}
std::random_shuffle(deck.begin(), deck.end());
handA = { deck.begin(), deck.begin() + 26 };
handB = { deck.begin() + 26, deck.end() };
}
void next_turn() {
card cardA = handA.front(); handA.erase(handA.begin());
card cardB = handB.front(); handB.erase(handB.begin());
tabledCards.emplace_back(cardA);
tabledCards.emplace_back(cardB);
int32_t rankA = getRank(cardA.pip);
int32_t rankB = getRank(cardB.pip);
std::cout << cardA.pip << cardA.suit << " " << cardB.pip << cardB.suit << std::endl;
if ( rankA > rankB ) {
std::cout << " Player A takes the cards" << std::endl;
std::random_shuffle(tabledCards.begin(), tabledCards.end());
handA.insert(handA.end(), tabledCards.begin(), tabledCards.end());
tabledCards.clear();
} else if ( rankA < rankB ) {
std::cout << " Player B takes the cards" << std::endl;
std::random_shuffle(tabledCards.begin(), tabledCards.end());
handB.insert(handB.end(), tabledCards.begin(), tabledCards.end());;
tabledCards.clear();
} else {
std::cout << " War!" << std::endl;
if ( game_over() ) {
return;
}
card cardAA = handA.front(); handA.erase(handA.begin());
card cardBB = handB.front(); handB.erase(handB.begin());
tabledCards.emplace_back(cardAA);
tabledCards.emplace_back(cardBB);
std::cout << "? ? Cards are face down" << std::endl;
if ( game_over() ) {
return;
}
next_turn();
}
}
bool game_over() const {
return handA.size() == 0 || handB.size() == 0;
}
void declare_winner() const {
if ( handA.size() == 0 && handB.size() == 0 ) {
std::cout << "The game ended in a tie" << std::endl;
} else if ( handA.size() == 0 ) {
std::cout << "Player B has won the game" << std::endl;
} else {
std::cout << "Player A has won the game" << std::endl;
}
}
private:
class card {
public:
card(const char suit, const char pip) : suit(suit), pip(pip) {};
char suit, pip;
};
int32_t getRank(const char ch) const {
auto it = find(PIPS.begin(), PIPS.end(), ch);
if ( it != PIPS.end() ) {
return it - PIPS.begin();
}
return -1;
}
std::vector<card> deck, handA, handB, tabledCards;
inline static const std::vector<char> PIPS = { '2', '3', '4', '5', '6', '7', '8', '9', 'T', 'J', 'Q', 'K', 'A' };
inline static const std::vector<char> SUITS = { 'C', 'D', 'H', 'S' };
};
int main() {
war_game wargame;
srand((unsigned) time(NULL));
while ( ! wargame.game_over() ) {
wargame.next_turn();
}
wargame.declare_winner();
}
```

- Output:

JD 9D Player A takes the cards TH 7S Player A takes the cards 6H QC Player B takes the cards 9C 9H War! ? ? Cards are face down AC 3C Player A takes the cards ... many lines elided 3D 6C Player B takes the cards 6D 4D Player A takes the cards JD 2C Player A takes the cards 3C 3D War! ? ? Cards are face down Player A has won the game

## FreeBASIC

```
Dim Shared As Integer stack(1, 51) ' each player's stack of cards (52 maximum)
Dim Shared As Integer inx(1) ' index to last card (+1) for each stack
Dim Shared As Integer carta
Sub MoveCard(hacia As Integer, desde As Integer) ' Move top card desde stack to bottom of To stack
Dim As Integer i
carta = stack(desde, 0) ' take top carta from desde stack
For i = 0 To inx(desde) - 2 ' shift remaining cards over
stack(desde, i) = stack(desde, i + 1)
Next i
If inx(desde) > 0 Then inx(desde) -= 1 ' remove desde card from its stack
stack(hacia, inx(hacia)) = carta ' add carta to bottom of To stack
If inx(hacia) < 52 Then inx(hacia) += 1 ' remove desde card from its stack
End Sub
Dim As String suit = "HDCS "
Dim As String rank = "23456789TJQKA "
Dim As Integer top ' index to compared cards, = stack top if not war
Dim As Integer deck(51) ' initial card deck (low 2 bits = suit)
For carta = 0 To 51 ' make a complete deck of cards
deck(carta) = carta
Next carta
Dim As Integer n, i, j, p, t
Randomize Timer
For n = 0 To 10000 ' shuffle the deck by swapping random locations
i = Int(Rnd * 52): j = Int(Rnd * 52)
Swap deck(i), deck(j)
Next n
For n = 0 To 51 ' deal deck into two stacks
carta = deck(n)
i = n \ 2
p = n Mod 2
stack(p, i) = carta
Next n
inx(0) = 52 \ 2: inx(1) = 52 \ 2 ' set indexes to last card +1
Do
For p = 0 To 1 ' show both stacks of cards
For i = 0 To inx(p) - 1
carta = stack(p, i)
Print Left(rank, carta Shr 2);
Next i
Print
For i = 0 To inx(p) - 1
carta = stack(p, i)
Print Mid(suit, (carta And 3) + 1, 1);
Next i
Print
Next p
If inx(0) = 0 Or inx(1) = 0 Then Exit Do ' game over
top = 0 ' compare card ranks (above 2-bit suits)
Do
If (stack(0, top) Shr 2) = (stack(1, top) Shr 2) Then
Color 3 : Print "War!" : Print : Color 7
top += 2 ' play a card down and a card up
Elseif (stack(0, top) Shr 2) > (stack(1, top) Shr 2) Then
For i = 0 To top ' move cards to stack 0
MoveCard(0, 0): MoveCard(0, 1)
Next i
Exit Do
Else
For i = 0 To top ' move cards to stack 1
MoveCard(1, 1): MoveCard(1, 0)
Next i
Exit Do
End If
Loop
Sleep 1000, 1
Print
Loop
End
```

## Go

```
package main
import (
"fmt"
"math/rand"
"time"
)
var suits = []string{"♣", "♦", "♥", "♠"}
var faces = []string{"2", "3", "4", "5", "6", "7", "8", "9", "T", "J", "Q", "K", "A"}
var cards = make([]string, 52)
var ranks = make([]int, 52)
func init() {
for i := 0; i < 52; i++ {
cards[i] = fmt.Sprintf("%s%s", faces[i%13], suits[i/13])
ranks[i] = i % 13
}
}
func war() {
deck := make([]int, 52)
for i := 0; i < 52; i++ {
deck[i] = i
}
rand.Shuffle(52, func(i, j int) {
deck[i], deck[j] = deck[j], deck[i]
})
hand1 := make([]int, 26, 52)
hand2 := make([]int, 26, 52)
for i := 0; i < 26; i++ {
hand1[25-i] = deck[2*i]
hand2[25-i] = deck[2*i+1]
}
for len(hand1) > 0 && len(hand2) > 0 {
card1 := hand1[0]
copy(hand1[0:], hand1[1:])
hand1[len(hand1)-1] = 0
hand1 = hand1[0 : len(hand1)-1]
card2 := hand2[0]
copy(hand2[0:], hand2[1:])
hand2[len(hand2)-1] = 0
hand2 = hand2[0 : len(hand2)-1]
played1 := []int{card1}
played2 := []int{card2}
numPlayed := 2
for {
fmt.Printf("%s\t%s\t", cards[card1], cards[card2])
if ranks[card1] > ranks[card2] {
hand1 = append(hand1, played1...)
hand1 = append(hand1, played2...)
fmt.Printf("Player 1 takes the %d cards. Now has %d.\n", numPlayed, len(hand1))
break
} else if ranks[card1] < ranks[card2] {
hand2 = append(hand2, played2...)
hand2 = append(hand2, played1...)
fmt.Printf("Player 2 takes the %d cards. Now has %d.\n", numPlayed, len(hand2))
break
} else {
fmt.Println("War!")
if len(hand1) < 2 {
fmt.Println("Player 1 has insufficient cards left.")
hand2 = append(hand2, played2...)
hand2 = append(hand2, played1...)
hand2 = append(hand2, hand1...)
hand1 = hand1[0:0]
break
}
if len(hand2) < 2 {
fmt.Println("Player 2 has insufficient cards left.")
hand1 = append(hand1, played1...)
hand1 = append(hand1, played2...)
hand1 = append(hand1, hand2...)
hand2 = hand2[0:0]
break
}
fdCard1 := hand1[0] // face down card
card1 = hand1[1] // face up card
copy(hand1[0:], hand1[2:])
hand1[len(hand1)-1] = 0
hand1[len(hand1)-2] = 0
hand1 = hand1[0 : len(hand1)-2]
played1 = append(played1, fdCard1, card1)
fdCard2 := hand2[0] // face down card
card2 = hand2[1] // face up card
copy(hand2[0:], hand2[2:])
hand2[len(hand2)-1] = 0
hand2[len(hand2)-2] = 0
hand2 = hand2[0 : len(hand2)-2]
played2 = append(played2, fdCard2, card2)
numPlayed += 4
fmt.Println("? \t? \tFace down cards.")
}
}
}
if len(hand1) == 52 {
fmt.Println("Player 1 wins the game!")
} else {
fmt.Println("Player 2 wins the game!")
}
}
func main() {
rand.Seed(time.Now().UnixNano())
war()
}
```

- Output:

Sample game (abridged):

9♠ Q♣ Player 2 takes the 2 cards. Now has 27. 7♠ 6♠ Player 1 takes the 2 cards. Now has 26. 3♠ 2♣ Player 1 takes the 2 cards. Now has 27. A♠ 2♦ Player 1 takes the 2 cards. Now has 28. K♠ Q♥ Player 1 takes the 2 cards. Now has 29. 6♥ 7♦ Player 2 takes the 2 cards. Now has 24. 2♥ T♣ Player 2 takes the 2 cards. Now has 25. 3♦ 4♠ Player 2 takes the 2 cards. Now has 26. Q♦ K♣ Player 2 takes the 2 cards. Now has 27. 7♥ 5♠ Player 1 takes the 2 cards. Now has 26. T♠ K♥ Player 2 takes the 2 cards. Now has 27. A♦ 9♣ Player 1 takes the 2 cards. Now has 26. 5♦ 5♥ War! ? ? Face down cards. 5♣ 2♠ Player 1 takes the 6 cards. Now has 29. ...... 6♣ 3♣ Player 1 takes the 2 cards. Now has 50. 3♥ T♥ Player 2 takes the 2 cards. Now has 3. K♥ 8♠ Player 1 takes the 2 cards. Now has 50. Q♣ T♥ Player 1 takes the 2 cards. Now has 51. 3♦ 3♥ War! Player 2 has insufficient cards left. Player 1 wins the game!

## J

Implementation:

```
DECK=: '2 3 4 5 6 7 8 9 10 J K Q A' (,' of ',])&.>/&cut '♣ ♦ ♥ ♠'
rank=: DECK {{ {."1 ($m)#:(,m) i. y }}
shuffle=: {~ ?~@#
deal=: _26 ]\ shuffle@,@DECK
cardwar=: {{
TURNS=: 0
'P1 P2'=: <each deal''
while. 0<P1 *&# P2 do. turn TURNS=: TURNS+1 end.
after=. ' after ',TURNS,&":' turn','s'#~1~:TURNS
if. #P1 do. 'Player 1 wins', after
elseif. #P2 do. 'Player 2 wins', after
else. 'Tie',after end.
}}
plays=: {{ ((m)=: }.".m)](echo n,~(m,' plays '),;'nothing'&[^:(0=#@]){.".m)]({.".m) }}
turn=: {{
c=. (b=. 'P2' plays''),(a =. 'P1' plays'')
while. a =&rank b do.
if. 0=P1 *&# P2 do. echo 'No more cards to draw' return. end.
c=. c, (a=. 'P1' plays''),(b =. 'P2' plays''), 'P1' plays' face down', 'P2' plays' face down'
end.
('P',":1+a <&rank b) takes ({~ ?~@#)c-.a:
}}
takes=: {{
(m)=: (".m),y
echo m,' takes ',;(<' and ') _2}}.,(<', '),.y
echo''
}}
```

Example run:

```
cardwar''
P1 plays 6 of ♦
P2 plays 9 of ♥
P2 takes 6 of ♦ and 9 of ♥
P1 plays K of ♣
P2 plays 6 of ♣
P1 takes K of ♣ and 6 of ♣
P1 plays A of ♦
P2 plays A of ♥
P2 plays 5 of ♠ face down
P1 plays J of ♥ face down
P2 plays 2 of ♣
P1 plays J of ♦
P1 takes A of ♥, J of ♥, A of ♦, 2 of ♣, 5 of ♠ and J of ♦
P1 plays 7 of ♥
P2 plays 10 of ♣
P2 takes 10 of ♣ and 7 of ♥
(... many lines deleted ...)
P1 plays 2 of ♦
P2 plays 5 of ♥
P2 takes 2 of ♦ and 5 of ♥
P1 plays K of ♥
P2 plays 4 of ♥
P1 takes 4 of ♥ and K of ♥
P1 plays 3 of ♦
P2 plays 3 of ♣
P2 plays 2 of ♦ face down
P1 plays 6 of ♠ face down
P2 plays 5 of ♥
P1 plays K of ♠
P1 takes 6 of ♠, K of ♠, 5 of ♥, 3 of ♣, 3 of ♦ and 2 of ♦
Player 1 wins after 86 turns
```

## Java

```
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
public final class WarCardGame {
public static void main(String[] args) {
WarGame warGame = new WarGame();
while ( ! warGame.gameOver() ) {
warGame.nextTurn();
}
warGame.declareWinner();
}
}
final class WarGame {
public WarGame() {
deck = new ArrayList<Card>(52);
for ( Character suit : SUITS ) {
for ( Character pip : PIPS ) {
deck.add( new Card(suit, pip) );
}
}
Collections.shuffle(deck);
handA = new ArrayList<Card>(deck.subList(0, 26));
handB = new ArrayList<Card>(deck.subList(26, 52));
tabledCards = new ArrayList<Card>();
}
public void nextTurn() {
Card cardA = handA.remove(0);
Card cardB = handB.remove(0);
tabledCards.add(cardA);
tabledCards.add(cardB);
int rankA = PIPS.indexOf(cardA.pip);
int rankB = PIPS.indexOf(cardB.pip);
System.out.print(cardA + " " + cardB);
if ( rankA > rankB ) {
System.out.println(" Player A takes the cards");
Collections.shuffle(tabledCards);
handA.addAll(tabledCards);
tabledCards.clear();
} else if ( rankA < rankB ) {
System.out.println(" Player B takes the cards");
Collections.shuffle(tabledCards);
handB.addAll(tabledCards);
tabledCards.clear();
} else {
System.out.println(" War!");
if ( gameOver() ) {
return;
}
Card cardAA = handA.remove(0);
Card cardBB = handB.remove(0);
tabledCards.add(cardAA);
tabledCards.add(cardBB);
System.out.println("? ? Cards are face down");
if ( gameOver() ) {
return;
}
nextTurn();
}
}
public boolean gameOver() {
return handA.size() == 0 || handB.size() == 0;
}
public void declareWinner() {
if ( handA.size() == 0 && handB.size() == 0 ) {
System.out.println("The game ended in a tie");
} else if ( handA.size() == 0 ) {
System.out.println("Player B has won the game");
} else {
System.out.println("Player A has won the game");
}
}
private record Card(Character suit, Character pip) {
@Override
public String toString() {
return "" + pip + suit;
}
}
private List<Card> deck, handA, handB, tabledCards;
private static final List<Character> PIPS =
Arrays.asList( '2', '3', '4', '5', '6', '7', '8', '9', 'T', 'J', 'Q', 'K', 'A' );
private static final List<Character> SUITS = List.of( 'C', 'D', 'H', 'S' );
}
```

- Output:

5H 7D Player B takes the cards QS 4C Player A takes the cards KS 4H Player A takes the cards 7S 7C War! ? ? Cards are face down 2D 4D Player B takes the cards 3H JC Player B takes the cards JD AH Player B takes the cards 8C 5S Player A takes the cards TH KH Player B takes the cards 9C QD Player B takes the cards 3C QH Player B takes the cards JH 9H Player A takes the cards 7H KC Player B takes the cards 9D 2C Player A takes the cards AS AD War! ? ? Cards are face down 5C QC Player B takes the cards 2S 9S Player B takes the cards 8D KD Player B takes the cards ... many lines elided 7S 9D Player B takes the cards 9H 2S Player A takes the cards 8D KS Player B takes the cards AH AC War! ? ? Cards are face down 2S 2H War! Player B has won the game

## Julia

```
# https://bicyclecards.com/how-to-play/war/
using Random
const SUITS = ["♣", "♦", "♥", "♠"]
const FACES = ["2", "3", "4", "5", "6", "7", "8", "9", "10", "J", "Q", "K", "A" ]
const DECK = vec([f * s for s in SUITS, f in FACES])
const rdict = Dict(DECK[i] => div(i + 3, 4) for i in eachindex(DECK))
deal2(deck) = begin d = shuffle(deck); d[1:2:51], d[2:2:52] end
function turn!(d1, d2, pending)
(isempty(d1) || isempty(d2)) && return false
c1, c2 = popfirst!(d1), popfirst!(d2)
r1, r2 = rdict[c1], rdict[c2]
print(rpad(c1, 10), rpad(c2, 10))
if r1 > r2
println("Player 1 takes the cards.")
push!(d1, c1, c2, pending...)
empty!(pending)
elseif r1 < r2
println("Player 2 takes the cards.")
push!(d2, c2, c1, pending...)
empty!(pending)
else # r1 == r2
println("Tie!")
(isempty(d1) || isempty(d2)) && return false
c3, c4 = popfirst!(d1), popfirst!(d2)
println(rpad("?", 10), rpad("?", 10), "Cards are face down.")
return turn!(d1, d2, push!(pending, c1, c2, c3, c4))
end
return true
end
function warcardgame()
deck1, deck2 = deal2(DECK)
while turn!(deck1, deck2, []) end
if isempty(deck2)
if isempty(deck1)
println("Game ends as a tie.")
else
println("Player 1 wins the game.")
end
else
println("Player 2 wins the game.")
end
end
warcardgame()
```

- Output:

5♦ 3♥ Player 1 takes the cards. 8♥ K♥ Player 2 takes the cards. 5♠ K♦ Player 2 takes the cards. 3♦ 6♥ Player 2 takes the cards. 9♣ J♠ Player 2 takes the cards. 8♦ 2♦ Player 1 takes the cards. J♣ 5♥ Player 1 takes the cards. 3♠ 4♥ Player 2 takes the cards. 9♥ A♣ Player 2 takes the cards. 9♠ 9♦ Tie! ? ? Cards are face down. A♠ 4♦ Player 1 takes the cards. 5♣ Q♠ Player 2 takes the cards. 6♦ 8♠ Player 2 takes the cards. 4♣ 10♦ Player 2 takes the cards. 4♠ 2♥ Player 1 takes the cards. Q♦ K♣ Player 2 takes the cards. A♥ 2♣ Player 1 takes the cards. Q♣ 2♠ Player 1 takes the cards. 10♥ 6♣ Player 1 takes the cards. ... many other lines ... 10♥ Q♣ Player 2 takes the cards. 4♣ 5♦ Player 2 takes the cards. A♣ 8♦ Player 1 takes the cards. 9♣ 2♣ Player 1 takes the cards. Q♥ Q♣ Tie! ? ? Cards are face down. Q♠ 5♦ Player 1 takes the cards. 8♥ 4♣ Player 1 takes the cards. Player 1 wins the game.

## Lua

```
-- main.lua
function newGame ()
-- new deck
local deck = {}
for iSuit = 1, #CardSuits do
for iRank = 1, #CardRanks do
local card = {
iSuit = iSuit,
iRank = iRank,
suit = CardSuits[iSuit],
rank = iRank,
name = CardRanks[iRank] .. CardSuits[iSuit]
}
local i = math.random (#deck + 1)
table.insert (deck, i, card)
end
end
-- new deal
Players = {
{index = 1, cards = {}},
{index = 2, cards = {}},
}
for i = 1, #deck/#Players do
for iPlayer = 1, #Players do
table.insert (Players[iPlayer].cards, table.remove(deck))
end
end
WarCards = {}
Turn = 1
Statistics = {}
end
function getHigherCard (cardA, cardB)
if cardA.rank > cardB.rank then
return cardA, 1
elseif cardA.rank < cardB.rank then
return cardB, 2
else
return nil
end
end
function love.load()
-- there is no card suits in the standard font
CardSuits = {"@", "#", "$", "%"}
CardRanks = {"2", "3", "4", "5", "6", "7", "8", "9", "10", "V", "Q", "K", "A"}
newGame ()
end
function love.draw()
for iPlayer = 1, #Players do
local player = Players[iPlayer]
love.graphics.print ('Player '..player.index, 50*(iPlayer-1), 0)
for iCard, card in ipairs (player.cards) do
love.graphics.print (card.name, 50*(iPlayer-1), 14*iCard)
end
end
for i = 1, math.min(40, #Statistics) do
local str = Statistics[i]
love.graphics.print (str, 150, 20+(i-1)*14)
end
end
function makeTurn ()
local card1 = table.remove (Players[1].cards)
local card2 = table.remove (Players[2].cards)
if card1 and card2 then
table.insert (WarCards, 1, card1)
table.insert (WarCards, math.random (1, 2), card2)
local winCard, index = getHigherCard (card1, card2)
if winCard then
table.insert (Statistics, 1, Turn .. ' Player ' .. index .. ' get ' .. #WarCards .. ' cards: ' .. card1.name .. ' vs ' .. card2.name)
for iCard = #WarCards, 1, -1 do
table.insert (Players[index].cards, 1, table.remove (WarCards))
end
elseif (#Players[1].cards > 0) and (#Players[2].cards > 0) then
-- start war
table.insert (Statistics, 1, Turn .. ' War: ' .. card1.name .. ' vs ' .. card2.name)
table.insert (WarCards, table.remove (Players[1].cards))
table.insert (WarCards, table.remove (Players[2].cards))
else
local index = 2
if #Players[1].cards == 0 then index = 1 end
table.insert (Statistics, 1, Turn .. ' Player ' .. index .. ' has no cards for this war.')
-- GameOver = true
end
Turn = Turn + 1
elseif GameOver then
GameOver = false
newGame ()
else
local index = 2
if #Players[1].cards > #Players[2].cards then index = 1 end
table.insert (Statistics, 1, Turn .. ' Player ' .. index .. ' wins the game!')
GameOver = true
end
end
function love.keypressed(key, scancode, isrepeat)
if false then
elseif key == "space" then
makeTurn ()
elseif scancode == "n" then
GameOver = false
newGame ()
elseif scancode == "q" then
local lastTurn = Turn
while not (GameOver or (Turn > lastTurn + 10000-1)) do
makeTurn ()
end
elseif key == "escape" then
love.event.quit()
end
if #Statistics > 40 then
local i = #Statistics, 40, -1 do
table.remove (Statistics, i)
end
end
end
function love.mousepressed( x, y, button, istouch, presses )
if button == 1 then -- left mouse button
makeTurn ()
elseif button == 2 then -- right mouse button
end
end
```

## Nim

We use module "playing_cards" from task https://rosettacode.org/wiki/Playing_cards.

```
import strformat
import playing_cards
const
None = -1
Player1 = 0
Player2 = 1
type Player = range[None..Player2]
const PlayerNames: array[Player1..Player2, string] = ["Player 1", "Player 2"]
#---------------------------------------------------------------------------------------------------
proc `<`(a, b: Card): bool =
## Compare two cards by their rank, Ace being the greatest.
if a.rank == Ace: false
elif b.rank == Ace: true
else: a.rank < b.rank
#---------------------------------------------------------------------------------------------------
proc displayRound(round: int; hands: openArray[Hand]; card1, card2: string; text: string) =
## Display text for a round.
stdout.write &"Round {round:<4} "
stdout.write &"Cards: {hands[Player1].len:>2}/{hands[Player2].len:<2} "
stdout.write &"{card1:>3} {card2:>3} "
echo text
#---------------------------------------------------------------------------------------------------
proc outOfCards(player: Player) =
## Display a message when a player has run out of cards.
echo &"{PlayerNames[player]} has run out of cards."
#---------------------------------------------------------------------------------------------------
proc doRound(hands: var openArray[Hand]; num: Positive) =
## Execute a round.
var stack1, stack2: seq[Card]
var winner: Player = None
while winner == None:
let card1 = hands[Player1].draw()
let card2 = hands[Player2].draw()
stack1.add card1
stack2.add card2
if card1.rank != card2.rank:
winner = if card1 < card2: Player2 else: Player1
displayRound(num, hands, $card1, $card2, &"{PlayerNames[winner]} takes the cards.")
else:
# There is a war.
displayRound(num, hands, $card1, $card2, "This is a war.")
if hands[Player1].len == 0:
winner = Player2
elif hands[Player2].len == 0:
winner = Player1
else:
# Add a hidden card on stacks.
stack1.add hands[Player1].draw()
stack2.add hands[Player2].draw()
displayRound(num, hands, " ?", " ?", "Cards are face down.")
# Check if each player has enough cards to continue the war.
if hands[Player1].len == 0:
Player1.outOfCards()
winner = Player2
elif hands[Player2].len == 0:
Player2.outOfCards()
winner = Player1
# Update hands.
var stack = stack1 & stack2
stack.shuffle()
hands[winner] = stack & hands[winner]
#———————————————————————————————————————————————————————————————————————————————————————————————————
var deck = initDeck()
deck.shuffle()
var hands = deck.deal(2, 26)
var num = 0
while true:
inc num
hands.doRound(num)
if hands[Player1].len == 0:
echo "Player 2 wins this game."
break
if hands[Player2].len == 0:
echo "Player 1 wins this game."
break
```

- Output:

Example of a short game.

Round 1 Cards: 25/25 10♣ 5♠ Player 1 takes the cards. Round 2 Cards: 26/24 3♦ 7♦ Player 2 takes the cards. Round 3 Cards: 25/25 10♦ 10♥ This is a war. Round 3 Cards: 24/24 ? ? Cards are face down. Round 3 Cards: 23/23 A♦ 4♥ Player 1 takes the cards. Round 4 Cards: 28/22 4♠ J♦ Player 2 takes the cards. Round 5 Cards: 27/23 9♠ Q♣ Player 2 takes the cards. Round 6 Cards: 26/24 A♣ 2♦ Player 1 takes the cards. Round 7 Cards: 27/23 Q♦ 3♠ Player 1 takes the cards. Round 8 Cards: 28/22 5♥ 3♥ Player 1 takes the cards. Round 9 Cards: 29/21 2♥ 2♠ This is a war. Round 9 Cards: 28/20 ? ? Cards are face down. Round 9 Cards: 27/19 4♦ 10♠ Player 2 takes the cards. Round 10 Cards: 26/24 K♠ 6♣ Player 1 takes the cards. Round 11 Cards: 27/23 8♥ 7♣ Player 1 takes the cards. Round 12 Cards: 28/22 4♣ 5♦ Player 2 takes the cards. Round 13 Cards: 27/23 8♣ 8♦ This is a war. Round 13 Cards: 26/22 ? ? Cards are face down. Round 13 Cards: 25/21 9♦ 6♠ Player 1 takes the cards. Round 14 Cards: 30/20 K♥ 9♥ Player 1 takes the cards. Round 15 Cards: 31/19 J♠ 7♥ Player 1 takes the cards. Round 16 Cards: 32/18 J♣ K♦ Player 2 takes the cards. Round 17 Cards: 31/19 2♣ 3♣ Player 2 takes the cards. Round 18 Cards: 30/20 A♥ 6♥ Player 1 takes the cards. Round 19 Cards: 31/19 A♠ 6♦ Player 1 takes the cards. Round 20 Cards: 32/18 8♠ 5♣ Player 1 takes the cards. Round 21 Cards: 33/17 10♣ 7♦ Player 1 takes the cards. Round 22 Cards: 34/16 5♠ 3♦ Player 1 takes the cards. Round 23 Cards: 35/15 Q♥ 4♠ Player 1 takes the cards. Round 24 Cards: 36/14 10♦ J♦ Player 2 takes the cards. Round 25 Cards: 35/15 Q♠ 9♠ Player 1 takes the cards. Round 26 Cards: 36/14 A♦ Q♣ Player 1 takes the cards. Round 27 Cards: 37/13 4♥ 4♦ This is a war. Round 27 Cards: 36/12 ? ? Cards are face down. Round 27 Cards: 35/11 2♦ 10♠ Player 2 takes the cards. Round 28 Cards: 34/16 A♣ 2♠ Player 1 takes the cards. Round 29 Cards: 35/15 Q♦ 7♠ Player 1 takes the cards. Round 30 Cards: 36/14 3♠ 2♥ Player 1 takes the cards. Round 31 Cards: 37/13 5♥ 5♦ This is a war. Round 31 Cards: 36/12 ? ? Cards are face down. Round 31 Cards: 35/11 6♣ J♣ Player 2 takes the cards. Round 32 Cards: 34/16 K♠ K♦ This is a war. Round 32 Cards: 33/15 ? ? Cards are face down. Round 32 Cards: 32/14 7♣ 2♣ Player 1 takes the cards. Round 33 Cards: 37/13 K♣ J♦ Player 1 takes the cards. Round 34 Cards: 38/12 6♠ 10♦ Player 2 takes the cards. Round 35 Cards: 37/13 J♥ 10♥ Player 1 takes the cards. Round 36 Cards: 38/12 8♣ 2♦ Player 1 takes the cards. Round 37 Cards: 39/11 9♦ 9♣ This is a war. Round 37 Cards: 38/10 ? ? Cards are face down. Round 37 Cards: 37/9 9♥ 10♠ Player 2 takes the cards. Round 38 Cards: 36/14 K♥ 4♦ Player 1 takes the cards. Round 39 Cards: 37/13 7♥ 6♣ Player 1 takes the cards. Round 40 Cards: 38/12 J♠ 5♥ Player 1 takes the cards. Round 41 Cards: 39/11 A♥ 4♣ Player 1 takes the cards. Round 42 Cards: 40/10 6♥ J♣ Player 2 takes the cards. Round 43 Cards: 39/11 A♠ 3♥ Player 1 takes the cards. Round 44 Cards: 40/10 6♦ 5♦ Player 1 takes the cards. Round 45 Cards: 41/9 8♠ 10♦ Player 2 takes the cards. Round 46 Cards: 40/10 5♣ 6♠ Player 2 takes the cards. Round 47 Cards: 39/11 7♦ 8♦ Player 2 takes the cards. Round 48 Cards: 38/12 10♣ 9♦ Player 1 takes the cards. Round 49 Cards: 39/11 3♦ 10♠ Player 2 takes the cards. Round 50 Cards: 38/12 5♠ 4♥ Player 1 takes the cards. Round 51 Cards: 39/11 4♠ 9♥ Player 2 takes the cards. Round 52 Cards: 38/12 Q♥ 9♣ Player 1 takes the cards. Round 53 Cards: 39/11 Q♠ 6♥ Player 1 takes the cards. Round 54 Cards: 40/10 9♠ J♣ Player 2 takes the cards. Round 55 Cards: 39/11 Q♣ 8♠ Player 1 takes the cards. Round 56 Cards: 40/10 A♦ 10♦ Player 1 takes the cards. Round 57 Cards: 41/9 A♣ 5♣ Player 1 takes the cards. Round 58 Cards: 42/8 2♠ 6♠ Player 2 takes the cards. Round 59 Cards: 41/9 Q♦ 7♦ Player 1 takes the cards. Round 60 Cards: 42/8 7♠ 8♦ Player 2 takes the cards. Round 61 Cards: 41/9 3♠ 3♦ This is a war. Round 61 Cards: 40/8 ? ? Cards are face down. Round 61 Cards: 39/7 7♣ 9♥ Player 2 takes the cards. Round 62 Cards: 38/12 8♥ 4♠ Player 1 takes the cards. Round 63 Cards: 39/11 K♦ 9♠ Player 1 takes the cards. Round 64 Cards: 40/10 2♣ J♣ Player 2 takes the cards. Round 65 Cards: 39/11 3♣ 2♠ Player 1 takes the cards. Round 66 Cards: 40/10 K♠ 6♠ Player 1 takes the cards. Round 67 Cards: 41/9 J♦ 7♠ Player 1 takes the cards. Round 68 Cards: 42/8 K♣ 8♦ Player 1 takes the cards. Round 69 Cards: 43/7 10♥ 10♠ This is a war. Round 69 Cards: 42/6 ? ? Cards are face down. Round 69 Cards: 41/5 8♣ 2♥ Player 1 takes the cards. Round 70 Cards: 46/4 2♦ 9♥ Player 2 takes the cards. Round 71 Cards: 45/5 K♥ 3♠ Player 1 takes the cards. Round 72 Cards: 46/4 4♦ 7♣ Player 2 takes the cards. Round 73 Cards: 45/5 7♥ 2♣ Player 1 takes the cards. Round 74 Cards: 46/4 6♣ J♣ Player 2 takes the cards. Round 75 Cards: 45/5 5♥ 2♦ Player 1 takes the cards. Round 76 Cards: 46/4 J♠ 9♥ Player 1 takes the cards. Round 77 Cards: 47/3 A♥ 7♣ Player 1 takes the cards. Round 78 Cards: 48/2 4♣ 4♦ This is a war. Round 78 Cards: 47/1 ? ? Cards are face down. Round 78 Cards: 46/0 A♠ J♣ Player 1 takes the cards. Player 1 wins this game.

## Perl

There are two players, 'one' and 'two'. This shows each players hand as the game progresses.

```
#!/usr/bin/perl
use strict; # https://rosettacode.org/wiki/War_Card_Game
use warnings;
use List::Util qw( shuffle );
my %rank;
@rank{ 2 .. 9, qw(t j q k a) } = 1 .. 13; # for winner
local $_ = join '', shuffle
map { my $f = $_; map $f.$_, qw( S H C D ) } 2 .. 9, qw( a t j q k );
substr $_, 52, 0, "\n"; # split deck into two parts
my $war = '';
my $cnt = 0;
$cnt++ while print( /(.*)\n(.*)/ && "one: $1\ntwo: $2\n\n" ),
s/^((.).)(.*)\n((?!\2)(.).)(.*)$/ my $win = $war; $war = ''; # capture
$rank{$2} > $rank{$5} ? "$3$1$4$win\n$6" : "$3\n$6$4$1$win" /e
||
s/^(.{4})(.*)\n(.{4})(.*)$/ print "WAR!!!\n\n"; $war .= "$1$3";
"$2\n$4" /e; # tie means war
print "player '", /^.{10}/ ? 'one' : 'two', "' wins in $cnt moves\n";
```

- Output:

one: 8CqCaD5H6S2HjC9S7HjH8S4DqD5C6DkC4H9D3DqHtC7C8DtS6C4S two: 5S8HaCaH2C6H3HaS7DjD3S2D5D9CkSkH9H4C2StDtHjSkD7SqS3C one: qCaD5H6S2HjC9S7HjH8S4DqD5C6DkC4H9D3DqHtC7C8DtS6C4S8C5S two: 8HaCaH2C6H3HaS7DjD3S2D5D9CkSkH9H4C2StDtHjSkD7SqS3C one: aD5H6S2HjC9S7HjH8S4DqD5C6DkC4H9D3DqHtC7C8DtS6C4S8C5SqC8H two: aCaH2C6H3HaS7DjD3S2D5D9CkSkH9H4C2StDtHjSkD7SqS3C WAR!!! one: 6S2HjC9S7HjH8S4DqD5C6DkC4H9D3DqHtC7C8DtS6C4S8C5SqC8H two: 2C6H3HaS7DjD3S2D5D9CkSkH9H4C2StDtHjSkD7SqS3C one: 2HjC9S7HjH8S4DqD5C6DkC4H9D3DqHtC7C8DtS6C4S8C5SqC8H6S2CaD5HaCaH two: 6H3HaS7DjD3S2D5D9CkSkH9H4C2StDtHjSkD7SqS3C ... (skipped middle part to save lines) one: kC7HkHqCqH9SjS5StD4D3S2HaD7S8H4CkS4SaHjD8D6H4H3HjC7CtH5DtC2DjH2C9D6D6C2S6SkDqD9H9C5HtS3D two: 8C7DaCqSaS5C8S3C one: 7HkHqCqH9SjS5StD4D3S2HaD7S8H4CkS4SaHjD8D6H4H3HjC7CtH5DtC2DjH2C9D6D6C2S6SkDqD9H9C5HtS3DkC8C two: 7DaCqSaS5C8S3C WAR!!! one: qCqH9SjS5StD4D3S2HaD7S8H4CkS4SaHjD8D6H4H3HjC7CtH5DtC2DjH2C9D6D6C2S6SkDqD9H9C5HtS3DkC8C two: qSaS5C8S3C WAR!!! one: 9SjS5StD4D3S2HaD7S8H4CkS4SaHjD8D6H4H3HjC7CtH5DtC2DjH2C9D6D6C2S6SkDqD9H9C5HtS3DkC8C two: 5C8S3C one: jS5StD4D3S2HaD7S8H4CkS4SaHjD8D6H4H3HjC7CtH5DtC2DjH2C9D6D6C2S6SkDqD9H9C5HtS3DkC8C9S5C7HkH7DaCqCqHqSaS two: 8S3C one: 5StD4D3S2HaD7S8H4CkS4SaHjD8D6H4H3HjC7CtH5DtC2DjH2C9D6D6C2S6SkDqD9H9C5HtS3DkC8C9S5C7HkH7DaCqCqHqSaSjS8S two: 3C one: tD4D3S2HaD7S8H4CkS4SaHjD8D6H4H3HjC7CtH5DtC2DjH2C9D6D6C2S6SkDqD9H9C5HtS3DkC8C9S5C7HkH7DaCqCqHqSaSjS8S5S3C two: player 'one' wins in 117 moves

## Phix

Shuffles on pickup to significantly shorten the games

with javascript_semantics sequence deck = shuffle(tagset(52)), hand1 = deck[1..26], hand2 = deck[27..52], pending = {} function pop1() integer res {res, hand1} = {hand1[1],hand1[2..$]} return res end function function pop2() integer res {res, hand2} = {hand2[1],hand2[2..$]} return res end function function show(integer c) integer r = remainder(c-1,13)+1, s = floor((c-1)/13)+1 printf(1,"%s ",{"23456789TJQKA"[r]&"SHDC"[s]}) return r end function while true do if length(hand1)=0 then if length(hand2)=0 then printf(1,"Game ends as a tie.\n") exit end if printf(1,"Player 2 wins the game.\n") exit elsif length(hand2)=0 then printf(1,"Player 1 wins the game.\n") exit end if integer c1 = pop1(), c2 = pop2(), r1 = show(c1), r2 = show(c2) if r1>r2 then printf(1,"Player 1 takes the cards.\n") hand1 &= shuffle(c1&c2&pending) pending = {} elsif r1<r2 then printf(1,"Player 2 takes the cards.\n") hand2 &= shuffle(c1&c2&pending) pending = {} else -- r1==r2 printf(1,"Tie!\n") if length(hand1)!=0 and length(hand2)!=0 then pending &= shuffle(c1&c2&pop1()&pop2()) printf(1,"?? ?? Cards are face down.\n") end if end if end while

- Output:

9H 3C Player 1 takes the cards. AD KD Player 1 takes the cards. 3D KS Player 2 takes the cards. ... 2H 9S Player 2 takes the cards. KC 7H Player 1 takes the cards. 5C JS Player 2 takes the cards. 3S 3D Tie! ?? ?? Cards are face down. 8D 2H Player 1 takes the cards. 2C JS Player 2 takes the cards. JD 5C Player 1 takes the cards. 6D 2C Player 1 takes the cards. QD JS Player 1 takes the cards. Player 1 wins the game.

## Python

```
""" https://bicyclecards.com/how-to-play/war/ """
from numpy.random import shuffle
SUITS = ['♣', '♦', '♥', '♠']
FACES = ['2', '3', '4', '5', '6', '7', '8', '9', '10', 'J', 'Q', 'K', 'A']
DECK = [f + s for f in FACES for s in SUITS]
CARD_TO_RANK = dict((DECK[i], (i + 3) // 4) for i in range(len(DECK)))
class WarCardGame:
""" card game War """
def __init__(self):
deck = DECK.copy()
shuffle(deck)
self.deck1, self.deck2 = deck[:26], deck[26:]
self.pending = []
def turn(self):
""" one turn, may recurse on tie """
if len(self.deck1) == 0 or len(self.deck2) == 0:
return self.gameover()
card1, card2 = self.deck1.pop(0), self.deck2.pop(0)
rank1, rank2 = CARD_TO_RANK[card1], CARD_TO_RANK[card2]
print("{:10}{:10}".format(card1, card2), end='')
if rank1 > rank2:
print('Player 1 takes the cards.')
self.deck1.extend([card1, card2])
self.deck1.extend(self.pending)
self.pending = []
elif rank1 < rank2:
print('Player 2 takes the cards.')
self.deck2.extend([card2, card1])
self.deck2.extend(self.pending)
self.pending = []
else: # rank1 == rank2
print('Tie!')
if len(self.deck1) == 0 or len(self.deck2) == 0:
return self.gameover()
card3, card4 = self.deck1.pop(0), self.deck2.pop(0)
self.pending.extend([card1, card2, card3, card4])
print("{:10}{:10}".format("?", "?"), 'Cards are face down.', sep='')
return self.turn()
return True
def gameover(self):
""" game over who won message """
if len(self.deck2) == 0:
if len(self.deck1) == 0:
print('\nGame ends as a tie.')
else:
print('\nPlayer 1 wins the game.')
else:
print('\nPlayer 2 wins the game.')
return False
if __name__ == '__main__':
WG = WarCardGame()
while WG.turn():
continue
```

- Output:

8♠ K♠ Player 2 takes the cards. 3♠ 8♥ Player 2 takes the cards. K♣ 4♠ Player 1 takes the cards. Q♦ J♣ Player 1 takes the cards. 5♦ 6♦ Player 2 takes the cards. A♥ Q♣ Player 1 takes the cards. 10♣ 5♥ Player 1 takes the cards. J♦ 7♣ Player 1 takes the cards. K♥ Q♠ Player 1 takes the cards. 2♦ 2♣ Player 1 takes the cards. 10♠ 9♥ Player 1 takes the cards. 9♠ 3♦ Player 1 takes the cards. A♠ A♦ Tie! ? ? Cards are face down. 3♥ 8♦ Player 2 takes the cards. 5♣ 2♠ Player 1 takes the cards. J♠ 4♦ Player 1 takes the cards. 2♥ 7♦ Player 2 takes the cards. ... et cetera ... A♣ 4♣ Player 1 takes the cards. 7♣ 3♣ Player 1 takes the cards. 9♠ A♦ Player 2 takes the cards. 6♦ Q♠ Player 2 takes the cards. 7♦ 3♦ Player 1 takes the cards. 5♥ 2♥ Player 1 takes the cards. A♣ A♥ Player 2 takes the cards. 4♣ 10♣ Player 2 takes the cards. 7♣ 10♥ Player 2 takes the cards. 3♣ 5♦ Player 2 takes the cards. 7♦ K♦ Player 2 takes the cards. 3♦ 8♣ Player 2 takes the cards. 5♥ J♦ Player 2 takes the cards. 2♥ 6♥ Player 2 takes the cards. Player 2 wins the game.

## Racket

(and inspired by Raku's thnudergnat rules)

```
#lang racket
(define current-battle-length (make-parameter 3))
(define cards (string->list (string-append "🂢🂣🂤🂥🂦🂧🂨🂩🂪🂫🂭🂮🂡" "🂲🂳🂴🂵🂶🂷🂸🂹🂺🂻🂽🂾🂱"
"🃂🃃🃄🃅🃆🃇🃈🃉🃊🃋🃍🃎🃁" "🃒🃓🃔🃕🃖🃗🃘🃙🃚🃛🃝🃞🃑")))
(define face (curry hash-ref (for/hash ((c cards) (i (in-naturals))) (values c (+ 2 (modulo i 13))))))
(define (print-draw-result turn-number d1 c1 d2 c2 → (pending null))
(printf "#~a\t~a ~a ~a\t~a|~a|~a~%" turn-number c1 → c2 (length d1) (length pending)(length d2)))
(define (turn d1 d2 (n 1) (pending null) (battle 0))
(match* (d1 d2)
[('() '()) "Game ends in a tie!"]
[(_ '()) "Player 1 wins."]
[('() _) "Player 2 wins."]
[((list c3 d1- ...) (list c4 d2- ...))
#:when (positive? battle)
(define pending+ (list* c3 c4 pending))
(print-draw-result n d1- "🂠" d2- "🂠" "?" pending+)
(turn d1- d2- (add1 n) pending+ (sub1 battle))]
[((list (and c1 (app face r)) d1- ...) (list (and c2 (app face r)) d2- ...))
(define pending+ (list* c1 c2 pending))
(print-draw-result n d1- c1 d2- c2 #\= pending+)
(turn d1- d2- (add1 n) pending+ (current-battle-length))]
[((list (and c1 (app face r1)) d1- ...) (list (and c2 (app face r2)) d2- ...))
(define spoils (shuffle (list* c1 c2 pending)))
(define p1-win? (> r1 r2))
(define d1+ (if p1-win? (append d1- spoils) d1-))
(define d2+ (if p1-win? d2- (append d2- spoils)))
(print-draw-result n d1+ c1 d2+ c2 (if p1-win? "←" "→"))
(turn d1+ d2+ (add1 n))]))
(define (war-card-game)
(call-with-values (λ () (split-at (shuffle cards) (quotient (length cards) 2)))
turn))
(displayln (war-card-game))
```

- Output:

#1 🃉 ← 🃔 27|0|25 #2 🂡 ← 🃘 28|0|24 #3 🂹 → 🃁 27|0|25 #4 🃋 → 🂽 26|0|26 #5 🂫 ← 🂪 27|0|25 #6 🃒 → 🃛 26|0|26 #7 🃑 ← 🃖 27|0|25 #8 🂢 → 🂻 26|0|26 #9 🃍 ← 🃗 27|0|25 #10 🃊 → 🃝 26|0|26 #11 🃎 ← 🂳 27|0|25 #12 🃅 → 🂶 26|0|26 #13 🃙 ← 🂨 27|0|25 #14 🂦 → 🂺 26|0|26

...

#305 🂧 → 🂾 45|0|7 #306 🂦 = 🃖 44|2|6 #307 🂠 ? 🂠 43|4|5 #308 🂠 ? 🂠 42|6|4 #309 🂠 ? 🂠 41|8|3 #310 🃁 ← 🃃 50|0|2 #311 🂽 ← 🂧 51|0|1 #312 🃘 → 🂾 50|0|2 #313 🂷 → 🂾 49|0|3 #314 🂴 → 🃘 48|0|4 #315 🃊 → 🂾 47|0|5 #316 🂱 ← 🂷 48|0|4 #317 🃋 ← 🂴 49|0|3 #318 🃒 → 🃘 48|0|4 #319 🂶 → 🃊 47|0|5 #320 🂢 → 🂾 46|0|6 #321 🂺 ← 🃒 47|0|5 #322 🂩 ← 🃘 48|0|4 #323 🃛 ← 🂶 49|0|3 #324 🃝 ← 🃊 50|0|2 #325 🃞 = 🂾 49|2|1 #326 🂠 ? 🂠 48|4|0 Player 1 wins.

(And the draw-3 rules were meant to lead to short games hmm?)

## Raku

The linked Bicycle cards site has slightly different rules for War! than how I used to play when I was but a lad. Implement it both ways.

Some rules are not nailed down very well. Here is how I interpreted it:

- The values of the cards 2-10 are face value; Jack, Queen, King and Ace may effectively be treated as: 11, 12, 13 & 14.
- Each player plays one card face up. The player whose card is the highest value takes both of the played cards and adds them to the bottom of his deck.
- When one player runs out of cards and is not able to place enough cards to finish a round, he loses.
- If both players play a card of the same value, it is then War!
**Bicycle rules:**each player then plays another card face down then another face up.**thundergnat rules:**each player then plays*three*cards face down then another face up. (Tends to make for shorter games.)- If the final face-up cards are different, the player playing the higher value card takes all of the played cards and adds them to the bottom of his deck
- If they are the same, continue with rounds of War! until one player plays a higher value war card or a player runs out of cards.

- When the winning player picks up his cards. the cards are randomized when added to the bottom of his deck. (Cuts a typical game from multi thousands of rounds to multi hundreds of rounds)

Pass in which variant you want to play 2 down, (Bicycle), `--war=2`

, 4 down (thundergnat), (default), `--war=4`

or 3 down (????) , `--war=3`

. By default, there is a short delay (.1 seconds) between rounds so you can watch what is going on. Pass in a larger/smaller value to slow down or speed up how long the game takes. `--sleep=0`

or whatever.

In glorious ANSI color! (The output loses much when pasted in as text so show output as screenshot images.)

```
unit sub MAIN (:$war where 2..4 = 4, :$sleep = .1);
my %c = ( # convenience hash of ANSI colors
red => "\e[38;2;255;10;0m",
blue => "\e[38;2;05;10;200m",
black => "\e[38;2;0;0;0m"
);
my @cards = flat (flat
<🂢 🂣 🂤 🂥 🂦 🂧 🂨 🂩 🂪 🂫 🂭 🂮 🂡
🃒 🃓 🃔 🃕 🃖 🃗 🃘 🃙 🃚 🃛 🃝 🃞 🃑>.map({ "{%c<black>}$_" }),
<🂲 🂳 🂴 🂵 🂶 🂷 🂸 🂹 🂺 🂻 🂽 🂾 🂱
🃂 🃃 🃄 🃅 🃆 🃇 🃈 🃉 🃊 🃋 🃍 🃎 🃁>.map({ "{%c<red>}$_" })
).batch(13).map({ .flat Z 2..14 })».map: { .[1] but .[0] };
my $back = "{%c<blue>}🂠";
my @won = <👈 👉>;
sub shuffle (@cards) { @cards.pick: * }
sub deal (@cards) { [@cards[0,*+2 … *], @cards[1,*+2 … *]] }
my ($rows, $cols) = qx/stty size/.words».Int; # get the terminal size
note "Terminal is only $cols characters wide, needs to be at least 80, 120 or more recommended."
and exit if $cols < 80;
sub clean-up {
reset-scroll-region;
show-cursor;
print-at $rows, 1, '';
print "\e[0m";
exit(0)
}
signal(SIGINT).tap: { clean-up() }
my @index = ($cols div 2 - 5, $cols div 2 + 4);
my @player = (deal shuffle @cards)».Array;
my $lose = False;
sub take (@player, Int $cards) {
if +@player >= $cards {
return @player.splice(0, $cards);
}
else {
$lose = True;
return @player.splice(0, +@player);
}
}
use Terminal::ANSI;
clear-screen;
hide-cursor;
# Set background color
print "\e[H\e[J\e[48;2;245;245;245m", ' ' xx $rows * $cols + 1;
# Add header
print-at 1, $cols div 2 - 1, "{%c<red>}WAR!";
print-at 2, 1, '━' x $cols;
my $row = 3;
my $height = $rows - $row - 2;
set-scroll-region($row, $height);
# footer
print-at $height + 1, 1, '━' x $cols;
my $round = 0;
my @round;
loop {
@round = [@player[0].&take(1)], [@player[1].&take(1)] unless +@round;
print-at $row, $cols div 2, "{%c<red>}┃";
print-at $row, @index[0], @round[0;0] // ' ';
print-at $row, @index[1], @round[1;0] // ' ';
if $lose {
if @player[0] < @player[1] {
print-at $row, $cols div 2 + 1, @won[1] unless +@round[1] == 1;
print-at $height + 3, $cols div 2 - 10, "{%c<red>} Player 1 is out of cards "
} else {
print-at $row, $cols div 2 - 2, @won[0] unless +@round[0] == 1;
print-at $height + 3, $cols div 2 - 10, "{%c<red>} Player 2 is out of cards "
}
}
if (@round[0].tail // 0) > (@round[1].tail // 0) {
print-at $row, $cols div 2 - 2, @won[0];
@player[0].append: flat (|@round[0],|@round[1]).pick: *;
@round = ();
}
elsif (@round[0].tail // 0) < (@round[1].tail // 0) {
print-at $row, $cols div 2 + 1, @won[1];
@player[1].append: flat (|@round[0],|@round[1]).pick: *;
@round = ();
}
else {
@round[0].append: @player[0].&take($war);
@round[1].append: @player[1].&take($war);
print-at $row, @index[0] - $_ * 2, ($_ %% $war) ?? @round[0; $_] !! $back for ^@round[0];
print-at $row, @index[1] + $_ * 2, ($_ %% $war) ?? @round[1; $_] !! $back for ^@round[1];
next
}
last if $lose;
print-at $height + 2, $cols div 2 - 4, "{%c<blue>} Round {++$round} ";
print-at $height + 2, $cols div 2 - 40, "{%c<blue>} Player 1: {+@player[0]} cards ";
print-at $height + 2, $cols div 2 + 21, "{%c<blue>} Player 2: {+@player[1]} cards ";
sleep $sleep if +$sleep;
if $row >= $height { scroll-up } else { ++$row }
}
# game over
print-at $height + 2, $cols div 2 - 40, "{%c<blue>} Player 1: {+@player[0] ?? '52' !! "{%c<red>}0"}{%c<blue>} cards ";
print-at $height + 2, $cols div 2 + 20, "{%c<blue>} Player 2: {+@player[1] ?? '52' !! "{%c<red>}0"}{%c<blue>} cards ";
clean-up;
```

- Sample outout Bicycle:

Pass in `:war=2`

on the command line.
See Bicycle variation (offsite png image)

- Sample outout using defaults:

See thundergnat variation (offsite png image)

## Wren

I've assumed that if a player runs out of cards during a 'war', then the other player automatically wins the game. The Bicycle card company's rules don't appear to cover this eventuality

I've also assumed that if a player wins a round, his/her own cards (in the order played) are added back to the bottom of his/her hand before the other player's cards.

```
import "random" for Random
import "./queue" for Deque
var rand = Random.new()
var suits = ["♣", "♦", "♥", "♠"]
var faces = ["2", "3", "4", "5", "6", "7", "8", "9", "T", "J", "Q", "K", "A" ]
var cards = List.filled(52, null)
for (i in 0..51) cards[i] = "%(faces[i%13])%(suits[(i/13).floor])"
var ranks = List.filled(52, 0)
for (i in 0..51) ranks[i] = i % 13
var war = Fn.new {
var deck = List.filled(52, 0)
for (i in 0..51) deck[i] = i
rand.shuffle(deck)
var hand1 = Deque.new()
var hand2 = Deque.new()
for (i in 0..25) {
hand1.pushFront(deck[2*i])
hand2.pushFront(deck[2*i+1])
}
while (hand1.count > 0 && hand2.count > 0) {
var card1 = hand1.popFront()
var card2 = hand2.popFront()
var played1 = [card1]
var played2 = [card2]
var numPlayed = 2
while (true) {
System.write("%(cards[card1])\t%(cards[card2])\t")
if (ranks[card1] > ranks[card2]) {
hand1.pushAllBack(played1)
hand1.pushAllBack(played2)
System.print("Player 1 takes the %(numPlayed) cards. Now has %(hand1.count).")
break
} else if (ranks[card1] < ranks[card2]) {
hand2.pushAllBack(played2)
hand2.pushAllBack(played1)
System.print("Player 2 takes the %(numPlayed) cards. Now has %(hand2.count).")
break
} else {
System.print("War!")
if (hand1.count < 2) {
System.print("Player 1 has insufficient cards left.")
hand2.pushAllBack(played2)
hand2.pushAllBack(played1)
hand2.pushAllBack(hand1)
hand1.clear()
break
}
if (hand2.count < 2) {
System.print("Player 2 has insufficient cards left.")
hand1.pushAllBack(played1)
hand1.pushAllBack(played2)
hand1.pushAllBack(hand2)
hand2.clear()
break
}
played1.add(hand1.popFront()) // face down card
card1 = hand1.popFront() // face up card
played1.add(card1)
played2.add(hand2.popFront()) // face down card
card2 = hand2.popFront() // face up card
played2.add(card2)
numPlayed = numPlayed + 4
System.print("? \t? \tFace down cards.")
}
}
}
if (hand1.count == 52) {
System.print("Player 1 wins the game!")
} else {
System.print("Player 2 wins the game!")
}
}
war.call()
```

- Output:

Sample game (abridged):

Q♥ 9♠ Player 1 takes the 2 cards. Now has 27. 3♦ T♦ Player 2 takes the 2 cards. Now has 26. 8♣ A♥ Player 2 takes the 2 cards. Now has 27. 3♠ Q♠ Player 2 takes the 2 cards. Now has 28. J♠ 4♥ Player 1 takes the 2 cards. Now has 25. 3♣ 7♣ Player 2 takes the 2 cards. Now has 28. 9♦ 2♠ Player 1 takes the 2 cards. Now has 25. 7♥ K♦ Player 2 takes the 2 cards. Now has 28. 5♥ A♠ Player 2 takes the 2 cards. Now has 29. 2♦ K♠ Player 2 takes the 2 cards. Now has 30. 5♠ 5♣ War! ? ? Face down cards. 4♣ T♣ Player 2 takes the 6 cards. Now has 33. A♦ 9♥ Player 1 takes the 2 cards. Now has 20. T♥ 9♣ Player 1 takes the 2 cards. Now has 21. K♣ Q♣ Player 1 takes the 2 cards. Now has 22. 4♦ A♣ Player 2 takes the 2 cards. Now has 31. 7♠ 7♦ War! ? ? Face down cards. 8♦ J♣ Player 2 takes the 6 cards. Now has 34. ..... T♠ 7♦ Player 1 takes the 2 cards. Now has 10. 7♠ J♣ Player 2 takes the 2 cards. Now has 43. 4♣ 4♥ War! ? ? Face down cards. 2♠ 2♣ War! ? ? Face down cards. 3♦ 9♠ Player 2 takes the 10 cards. Now has 48. 5♠ 5♣ War! ? ? Face down cards. T♠ T♥ War! Player 1 has insufficient cards left. Player 2 wins the game!

## XPL0

```
char Deck(52), \initial card deck (low 2 bits = suit)
Stack(2, 52); \each player's stack of cards (52 maximum)
int Inx(2), \index to last card (+1) for each stack
Top, \index to compared cards, = stack top if not war
Card, N, I, J, P, T;
char Suit, Rank;
proc MoveCard(To, From); \Move top card From Stack to bottom of To Stack
int To, From;
int Card, I;
[Card:= Stack(From, 0); \take top Card from From Stack
for I:= 0 to Inx(From)-2 do \shift remaining cards over
Stack(From, I):= Stack(From, I+1);
if Inx(From) > 0 then \remove From card from its Stack
Inx(From):= Inx(From)-1;
Stack(To, Inx(To)):= Card; \add Card to bottom of To Stack
if Inx(To) < 52 then \remove From card from its Stack
Inx(To):= Inx(To)+1;
];
[\\Suit:= "^C^D^E^F "; \IBM OEM card symbols aren't displayable on RC
Suit:= "HDCS ";
Rank:= "23456789TJQKA "; \T = 10
for Card:= 0 to 52-1 do \make a complete deck of cards
Deck(Card):= Card;
for N:= 0 to 10_000 do \shuffle the deck by swapping random locations
[I:= Ran(52); J:= Ran(52);
T:= Deck(I); Deck(I):= Deck(J); Deck(J):= T;
];
for N:= 0 to 52-1 do \deal deck into two stacks
[Card:= Deck(N);
I:= N/2;
P:= rem(0);
Stack(P, I):= Card;
];
Inx(0):= 52/2; Inx(1):= 52/2; \set indexes to last card +1
loop [for P:= 0 to 1 do \show both stacks of cards
[for I:= 0 to Inx(P)-1 do
[Card:= Stack(P, I); ChOut(0, Rank(Card>>2))];
CrLf(0);
for I:= 0 to Inx(P)-1 do
[Card:= Stack(P, I); ChOut(0, Suit(Card&3))];
CrLf(0);
];
if Inx(0)=0 or Inx(1)=0 then quit; \game over
Top:= 0; \compare card ranks (above 2-bit suits)
loop [if Stack(0, Top)>>2 = Stack(1, Top)>>2 then
[Text(0, "War!"); CrLf(0);
Top:= Top+2; \play a card down and a card up
]
else if Stack(0, Top)>>2 > Stack(1, Top)>>2 then
[for I:= 0 to Top do \move cards to Stack 0
[MoveCard(0, 0); MoveCard(0, 1)];
quit;
]
else [for I:= 0 to Top do \move cards to Stack 1
[MoveCard(1, 1); MoveCard(1, 0)];
quit;
];
];
T:= ChIn(1); \wait for keystroke (no key echo)
CrLf(0);
];
]
]
```

- Output:

578Q465J29A9437JTT59A662QJ CCDDCCSHSHHDDCHCSDHCDHSHHS KK8A975Q2A38J87T63K342TQK4 HCCCSDDCCSSSDHSHDHDDHDCSSS 78Q465J29A9437JTT59A662QJ CDDCCSHSHHDDCHCSDHCDHSHHS K8A975Q2A38J87T63K342TQK4K5 CCCSDDCCSSSDHSHDHDDHDCSSSHC 8Q465J29A9437JTT59A662QJ DDCCSHSHHDDCHCSDHCDHSHHS 8A975Q2A38J87T63K342TQK4K5K7 CCSDDCCSSSDHSHDHDDHDCSSSHCCC War! 65J29A9437JTT59A662QJ CSHSHHDDCHCSDHCDHSHHS 75Q2A38J87T63K342TQK4K5K788AQ94 DDCCSSSDHSHDHDDHDCSSSHCCCCDCDSC 5J29A9437JTT59A662QJ SHSHHDDCHCSDHCDHSHHS 5Q2A38J87T63K342TQK4K5K788AQ9476 DCCSSSDHSHDHDDHDCSSSHCCCCDCDSCDC War! War! 9437JTT59A662QJ55JQ229AA3 DDCHCSDHCDHSHHSSDHCSCHSHS 8J87T63K342TQK4K5K788AQ9476 SDHSHDHDDHDCSSSHCCCCDCDSCDC . . . K38562446952A7A2K4J4T7KJQ39976Q893ATK8JTT5Q562AQ87 DDSDSHHSDDSSDDCCSDHCSCCCSSHSSCCCCHSCHHDDHHDCHDHHDH J3 SC 38562446952A7A2K4J4T7KJQ39976Q893ATK8JTT5Q562AQ87KJ DSDSHHSDDSSDDCCSDHCSCCCSSHSSCCCCHSCHHDDHHDCHDHHDHDS 3 C War! 62446952A7A2K4J4T7KJQ39976Q893ATK8JTT5Q562AQ87KJ3385 SHHSDDSSDDCCSDHCSCCCSSHSSCCCCHSCHHDDHHDCHDHHDHDSDCSD