# Snake and ladder

*is a*

**Snake and ladder****draft**programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

- Task

Create a Snakes and Ladders game where the computer plays against a human player.

This game is also known as **Chutes and Ladders**.

For a board example you can use this image here: snakes & ledders.

(A **ledder** is the Old English word for a **ladder**.)

The way you'll represent the board and the players' tokens is totally up to you: graphics or ASCII graphics or even just text.

Happy coding.

## 11l

```
V snl = [4 = 14,
9 = 31,
17 = 7,
20 = 38,
28 = 84,
40 = 59,
51 = 67,
54 = 34,
62 = 19,
63 = 81,
64 = 60,
71 = 91,
87 = 24,
93 = 73,
95 = 75,
99 = 78]
V sixesRollAgain = 1B
F turn(player, =square)
L
V roll = random:(1 .. 6)
print(‘Player #. on square #., rolls a #.’.format(player, square, roll), end' ‘’)
I square + roll > 100
print(‘ but cannot move.’)
E
square += roll
print(‘ and moves to square #.’.format(square))
I square == 100
R 100
V next = :snl.get(square, square)
I square < next
print(‘Yay! landed on a ladder. Climb up to #..’.format(next))
I square == 100
R 100
square = next
E I square > next
print(‘Oops! Landed on a snake. Slither down to #..’.format(next))
square = next
I roll < 6 | !:sixesRollAgain
R square
print(‘Rolled a 6 so roll again.’)
F main()
V players = [1, 1, 1]
L
L(i) 0..2
V ns = turn(i + 1, players[i])
I ns == 100
print(‘Player #. wins!’.format(i + 1))
R
players[i] = ns
print()
main()
```

- Output:

The same as in Python.

## ALGOL 68

Fully automated game, the user is initially promoted for a number of players (up to 10, 0 or less exits without playing). The user is also prompted as to whether a player can win by reaching a square greater than the final one and also whether a player can throw again after throwing a 6.

```
BEGIN # Snakes and ladders game #
# create the board #
INT max square = 100;
[ 1 : max square ]INT board;
FOR i TO max square DO board[ i ] := 0 OD;
board[ 4 ] := 14;
board[ 9 ] := 31;
board[ 17 ] := 7;
board[ 20 ] := 38;
board[ 28 ] := 84;
board[ 40 ] := 59;
board[ 51 ] := 67;
board[ 54 ] := 34;
board[ 62 ] := 19;
board[ 63 ] := 81;
board[ 64 ] := 60;
board[ 71 ] := 91;
board[ 87 ] := 24;
board[ 93 ] := 73;
board[ 95 ] := 75;
board[ 99 ] := 78;
# get options #
INT players := 0;
WHILE print( ( "How many players ( 1-10, 0 or less to quit ) ? " ) );
read( ( players, newline ) );
players > 10
DO
print( ( "Too many players" ) )
OD;
IF players > 0 THEN
# the user does want to play #
BOOL win on gt max := FALSE;
WHILE print( ( "Allow position > ", whole( max square, 0 ), " to win [y/n] ? " ) );
CHAR c;
read( ( c, newline ) );
win on gt max := c = "y";
c /= "y" AND c /= "n"
DO SKIP OD;
BOOL extra roll for 6 := FALSE;
WHILE print( ( "Roll again on a 6 [y/n] ? " ) );
CHAR c;
read( ( c, newline ) );
extra roll for 6 := c = "y";
c /= "y" AND c /= "n"
DO SKIP OD;
[ 1 : players ]INT position;
FOR i TO players DO position[ i ] := 0 OD;
# play #
BOOL game over := FALSE;
WHILE NOT game over DO
# handle each players move #
print( ( newline ) );
FOR p TO players WHILE NOT game over DO
WHILE
INT roll = ENTIER ( next random * 6 ) + 1;
STRING player id = "Player " + whole( p, 0 );
print( ( player id
, IF position[ p ] < 1 THEN "" ELSE " (on square " + whole( position[ p ], 0 ) + ")" FI
, " rolls a "
, whole( roll, 0 )
, newline
)
);
IF position[ p ] + roll > max square
AND NOT win on gt max
THEN
# the player would be off the board #
print( ( " ", player id, " cannot move", newline ) )
ELSE
# the player can move roll squares #
position[ p ] +:= roll;
IF position[ p ] > max square THEN position[ p ] := max square FI;
print( ( " and moves to square ", whole( position[ p ], 0 ) ) );
IF board[ position[ p ] ] > position[ p ] THEN
# landed on a ladder #
position[ p ] := board[ position[ p ] ];
print( ( " - which is a ladder :) ", player id, " climbs to up ", whole( position[ p ], 0 ), newline ) )
ELIF board[ position[ p ] ] /= 0 THEN
# landed on a snake #
position[ p ] := board[ position[ p ] ];
print( ( " - which is a snake :( ", player id, " slides down to ", whole( position[ p ], 0 ), newline ) )
ELIF position[ p ] >= max square THEN
# the player has won #
print( ( " and wins the game!", newline ) );
game over := TRUE
ELSE
# not a ladder, snake or winning move #
print( ( newline ) )
FI
FI;
roll = 6 AND extra roll for 6 AND NOT game over
DO
print( ( player id, " can roll again...", newline ) )
OD
OD
OD
FI
END
```

- Output:

Sample game.

How many players ( 1-10, 0 or less to quit ) ? 4 Allow position > 100 to win [y/n] ? n Roll again on a 6 [y/n] ? y Player 1 rolls a 1 and moves to square 1 Player 2 rolls a 4 and moves to square 4 - which is a ladder :) Player 2 climbs to up 14 Player 3 rolls a 6 and moves to square 6 Player 3 can roll again... Player 3 (on square 6) rolls a 3 and moves to square 9 - which is a ladder :) Player 3 climbs to up 31 Player 4 rolls a 2 and moves to square 2 ... Player 1 (on square 36) rolls a 2 and moves to square 38 Player 2 (on square 84) rolls a 3 and moves to square 87 - which is a snake :( Player 2 slides down to 24 Player 3 (on square 44) rolls a 1 and moves to square 45 Player 4 (on square 14) rolls a 6 and moves to square 20 - which is a ladder :) Player 4 climbs to up 38 Player 4 can roll again... Player 4 (on square 38) rolls a 3 and moves to square 41 ... Player 1 (on square 79) rolls a 6 and moves to square 85 Player 1 can roll again... Player 1 (on square 85) rolls a 4 and moves to square 89 Player 2 (on square 92) rolls a 6 and moves to square 98 Player 2 can roll again... Player 2 (on square 98) rolls a 2 and moves to square 100 and wins the game!

## AWK

```
# syntax: GAWK -f SNAKE_AND_LADDER.AWK [players]
# example: GAWK -f SNAKE_AND_LADDER.AWK 3
BEGIN {
players = (ARGV[1] ~ /^[0-9]+$/) ? ARGV[1] : 2
load_board()
show_board()
if (players == 0) { exit(0) }
for (i=1; i<=players; i++) {
sq_arr[i] = 1 # all players start on square 1
}
srand() # seed rand() with time of day
while (1) {
printf("\nTurn #%d\n",++turns)
for (i=1; i<=players; i++) {
ns = turn(i,sq_arr[i])
if (ns == 100) {
printf("Player %d wins after %d moves\n",i,moves)
exit(0)
}
sq_arr[i] = ns
}
}
}
function load_board() {
# index < value is a ladder
# index > value is a snake
sl_arr[ 4] = 14
sl_arr[ 9] = 31
sl_arr[17] = 7
sl_arr[20] = 38
sl_arr[28] = 84
sl_arr[40] = 59
sl_arr[51] = 67
sl_arr[54] = 34
sl_arr[62] = 19
sl_arr[63] = 81
sl_arr[64] = 60
sl_arr[71] = 91
sl_arr[87] = 24
sl_arr[93] = 73
sl_arr[95] = 75
sl_arr[99] = 78
}
function show_board( board_arr,i,pos,row,L,S) {
PROCINFO["sorted_in"] = "@ind_num_asc"
# populate board with cell numbers
for (i=1; i<=100; i++) {
board_arr[i] = i
}
# add in Snakes & Ladders
for (i in sl_arr) {
board_arr[sl_arr[i]] = board_arr[i] = (i+0 < sl_arr[i]) ? sprintf("L%02d",++L) : sprintf("S%02d",++S)
}
# print board
print("board: L=ladder S=snake")
for (row=10; row>=1; row--) {
if (row ~ /[02468]$/) {
pos = row * 10
for (i=1; i<=10; i++) {
printf("%5s",board_arr[pos--])
}
}
else {
pos = row * 10 - 9
for (i=1; i<=10; i++) {
printf("%5s",board_arr[pos++])
}
}
printf("\n")
}
}
function turn(player,square, position,roll) {
while (1) {
moves++
roll = int(rand() * 6) + 1 # roll die
printf("Player %d on square %d rolls a %d",player,square,roll)
if (square + roll > 100) {
printf(" but cannot move\n")
}
else {
square += roll
printf(" and moves to square %d\n",square)
if (square == 100) {
return(100)
}
position = (square in sl_arr) ? sl_arr[square] : square
if (square < position) {
printf("Yay! Landed on a ladder so climb up to %d\n",position)
}
else if (position < square) {
printf("Oops! Landed on a snake so slither down to %d\n",position)
}
square = position
}
if (roll < 6) {
return(square)
}
printf("Rolled a 6 so roll again\n")
}
}
```

Sample command and output:

GAWK -f SNAKE_AND_LADDER.AWK 3 board: L=ladder S=snake 100 S08 98 97 96 S07 94 S06 92 L08 L07 82 83 L04 85 86 S05 88 89 90 80 79 S08 77 76 S07 74 S06 72 L08 61 S03 L07 S04 65 66 L06 68 69 70 S04 L05 58 57 56 55 S02 53 52 L06 41 42 43 44 45 46 47 48 49 50 L05 39 L03 37 36 35 S02 33 32 L02 21 22 23 S05 25 26 27 L04 29 30 L03 S03 18 S01 16 15 L01 13 12 11 1 2 3 L01 5 6 S01 8 L02 10 Turn #1 Player 1 on square 1 rolls a 4 and moves to square 5 Player 2 on square 1 rolls a 5 and moves to square 6 Player 3 on square 1 rolls a 3 and moves to square 4 Yay! Landed on a ladder so climb up to 14 Turn #2 Player 1 on square 5 rolls a 2 and moves to square 7 Player 2 on square 6 rolls a 6 and moves to square 12 Rolled a 6 so roll again Player 2 on square 12 rolls a 3 and moves to square 15 Player 3 on square 14 rolls a 2 and moves to square 16 Turn #3 Player 1 on square 7 rolls a 5 and moves to square 12 Player 2 on square 15 rolls a 1 and moves to square 16 Player 3 on square 16 rolls a 1 and moves to square 17 Oops! Landed on a snake so slither down to 7 ... Turn #44 Player 1 on square 98 rolls a 5 but cannot move Player 2 on square 47 rolls a 2 and moves to square 49 Player 3 on square 89 rolls a 5 and moves to square 94 Turn #45 Player 1 on square 98 rolls a 2 and moves to square 100 Player 1 wins after 155 moves

## BASIC

### BASIC256

```
arraybase 1
global SNL
map SNL
SNL[ 4] = 14
SNL[ 9] = 31
SNL[17] = 7
SNL[20] = 38
SNL[28] = 84
SNL[40] = 59
SNL[51] = 67
SNL[54] = 34
SNL[62] = 19
SNL[63] = 81
SNL[64] = 60
SNL[71] = 91
SNL[87] = 24
SNL[93] = 73
SNL[95] = 75
SNL[99] = 78
dim players(3)
players = {1, 1, 1}
do
for i = 1 to players[?]
ns = Turn(i, players[i - 1])
if ns = 100 then
print "Player "; i; " wins!"
exit do
end if
players[i - 1] = ns
print
next i
until False
end
function Turn(player, square)
sixesThrowAgain = True
do
roll = int(rand * 6)
print "Player "; player; ", on square "; square; ", rolls a "; roll;
if square + roll > 100 then
print " but cannot move."
else
square += roll
print " and moves to square "; square
if square = 100 then return 100
nxt = square
if SNL[square, square] then nxt = SNL[nxt, nxt]
if square < nxt then
print "Yay! Landed on a ladder. Climb up to "; nxt; "."
if nxt = 100 then return 100
square = nxt
else
if square > nxt then
print "Oops! Landed on a snake. Slither down to "; nxt; "."
square = nxt
end if
end if
end if
if roll < 6 or not sixesThrowAgain then return square
print "Rolled a 6 so roll again."
until False
end function
```

## C

```
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
bool sixesThrowAgain = true;
void init() {
srand((unsigned int)time(NULL));
}
int rollDice() {
return rand() % 6 + 1;
}
int nextSquare(int square) {
switch (square) {
case 4: return 14;
case 9: return 31;
case 17: return 7;
case 20: return 38;
case 28: return 84;
case 40: return 59;
case 51: return 67;
case 54: return 34;
case 62: return 19;
case 63: return 81;
case 64: return 60;
case 71: return 91;
case 87: return 24;
case 93: return 73;
case 95: return 75;
case 99: return 78;
default: return square;
}
}
int turn(int player, int square) {
int roll, next;
while (true) {
roll = rollDice();
printf("Player %d, on square %d, rolls a %d", player, square, roll);
if (square + roll > 100) {
printf(" but cannot move.\n");
} else {
square += roll;
printf(" and moves to square %d\n", square);
if (square == 100) return 100;
next = nextSquare(square);
if (square < next) {
printf("Yay! Landed on a ladder. Climb up to %d.\n", next);
square = next;
} else if (next < square) {
printf("Oops! landed on a snake. Slither down to %d.\n", next);
square = next;
}
}
if (roll < 6 || !sixesThrowAgain) return square;
printf("Rolled a 6 so roll again.\n");
}
}
int main() {
int players[3] = { 1, 1, 1 };
int i, ns;
init();
while (true) {
for (i = 0; i < sizeof(players) / sizeof(int); ++i) {
ns = turn(i + 1, players[i]);
if (ns == 100) {
printf("Player %d wins!\n", i + 1);
goto out;
}
players[i] = ns;
printf("\n");
}
}
out:
return 0;
}
```

## C#

```
using System;
using System.Collections.Generic;
namespace SnakeAndLadder {
class Program {
private static Dictionary<int, int> snl = new Dictionary<int, int>() {
{4, 14},
{9, 31},
{17, 7},
{20, 38},
{28, 84},
{40, 59},
{51, 67},
{54, 34},
{62, 19},
{63, 81},
{64, 60},
{71, 91},
{87, 24},
{93, 73},
{95, 75},
{99, 78},
};
private static Random rand = new Random();
private const bool sixesThrowAgain = true;
static int Turn(int player, int square) {
while (true) {
int roll = rand.Next(1, 6);
Console.Write("Player {0}, on square {1}, rolls a {2}", player, square, roll);
if (square + roll > 100) {
Console.WriteLine(" but cannot move.");
} else {
square += roll;
Console.WriteLine(" and moves to square {0}", square);
if (square == 100) return 100;
int next = square;
if (snl.ContainsKey(square)) {
next = snl[square];
}
if (square < next) {
Console.WriteLine("Yay! Landed on a ladder. Climb up to {0}.", next);
if (next == 100) return 100;
square = next;
} else if (square > next) {
Console.WriteLine("Oops! Landed on a snake. Slither down to {0}.", next);
}
}
if (roll < 6 || !sixesThrowAgain) return square;
Console.WriteLine("Rolled a 6 so roll again.");
}
}
static void Main(string[] args) {
// three players atarting on square one
int[] players = { 1, 1, 1 };
while (true) {
for (int i = 0; i < players.Length; i++) {
int ns = Turn(i + 1, players[i]);
if (ns == 100) {
Console.WriteLine("Player {0} wins!", i + 1);
return;
}
players[i] = ns;
Console.WriteLine();
}
}
}
}
}
```

## C++

```
#include <iostream>
#include <map>
#include <random>
std::default_random_engine generator;
std::uniform_int_distribution<int> dice(1, 6);
int rollDice() {
return dice(generator);
}
const bool sixesThrowAgain = true;
const std::map<int, int> snl{
{4, 14},
{9, 31},
{17, 7},
{20, 38},
{28, 84},
{40, 59},
{51, 67},
{54, 34},
{62, 19},
{63, 81},
{64, 60},
{71, 91},
{87, 24},
{93, 73},
{95, 75},
{99, 78},
};
// taken from https://stackoverflow.com/a/2333816
template <template<class, class, class...> class C, typename K, typename V, typename... Args>
V GetWithDef(const C<K, V, Args...>& m, K const& key, const V & defval) {
typename C<K, V, Args...>::const_iterator it = m.find(key);
if (it == m.end())
return defval;
return it->second;
}
int turn(int player, int square) {
while (true) {
int roll = rollDice();
printf("Player %d, on square %d, rolls a %d", player, square, roll);
if (square + roll > 100) {
printf(" but cannot move.\n");
} else {
square += roll;
printf(" and moves to square %d\n", square);
if (square == 100) return 100;
int next = GetWithDef(snl, square, square);
if (square < next) {
printf("Yay! Landed on a ladder. Climb up to %d.\n", next);
square = next;
} else if (next < square) {
printf("Oops! landed on a snake. Slither down to %d.\n", next);
square = next;
}
}
if (roll < 6 || !sixesThrowAgain)return square;
printf("Rolled a 6 so roll again.\n");
}
}
int main() {
// three players starting on square one
int players[] = { 1, 1, 1 };
while (true) {
for (int i = 0; i < sizeof(players) / sizeof(int); ++i) {
int ns = turn(i + 1, players[i]);
if (ns == 100) {
printf("Player %d wins!\n", i + 1);
goto out;
}
players[i] = ns;
printf("\n");
}
}
out:
return 0;
}
```

## D

```
import std.stdio;
//Board layout, start square to end square
auto snl() {
// Workaround for not being able to static initialize an AA
int[int] temp;
temp[4] = 14;
temp[9] = 31;
temp[17] = 7;
temp[20] = 38;
temp[28] = 84;
temp[40] = 59;
temp[51] = 67;
temp[54] = 34;
temp[62] = 19;
temp[63] = 81;
temp[64] = 60;
temp[71] = 91;
temp[87] = 24;
temp[93] = 73;
temp[95] = 75;
temp[99] = 78;
return temp;
}
int turn(int player, int square) {
import std.random;
auto roll = uniform!"[]"(1, 6);
write("Player ", player, " on square ", square, " rolls a ", roll);
if (square + roll > 100) {
writeln(" but cannot move. Next players turn.");
return square;
} else {
square += roll;
writeln(" and moves to square ", square);
}
auto next = snl().get(square, square);
if (square < next) {
writeln("Yay! Landed on a ladder. Climb up to ", next);
} else if (square > next) {
writeln("Oops! Landed on a snake. Slither down to ", next);
}
return next;
}
void main() {
// three players starting on square one
auto players = [1, 1, 1];
while(true) {
foreach(i,s; players) {
auto ns = turn(i+1, s);
if (ns == 100) {
writeln("Player ", i+1, " wins!");
return;
}
players[i] = ns;
writeln;
}
}
}
```

- Output:

Player 1 on square 1 rolls a 5 and moves to square 6 Player 2 on square 1 rolls a 6 and moves to square 7 Player 3 on square 1 rolls a 5 and moves to square 6 Player 1 on square 6 rolls a 6 and moves to square 12 Player 2 on square 7 rolls a 4 and moves to square 11 Player 3 on square 6 rolls a 3 and moves to square 9 Yay! Landed on a ladder. Climb up to 31 Player 1 on square 12 rolls a 1 and moves to square 13 Player 2 on square 11 rolls a 1 and moves to square 12 Player 3 on square 31 rolls a 1 and moves to square 32 Player 1 on square 13 rolls a 5 and moves to square 18 Player 2 on square 12 rolls a 5 and moves to square 17 Oops! Landed on a snake. Slither down to 7 Player 3 on square 32 rolls a 5 and moves to square 37 Player 1 on square 18 rolls a 3 and moves to square 21 Player 2 on square 7 rolls a 2 and moves to square 9 Yay! Landed on a ladder. Climb up to 31 Player 3 on square 37 rolls a 3 and moves to square 40 Yay! Landed on a ladder. Climb up to 59 Player 1 on square 21 rolls a 3 and moves to square 24 Player 2 on square 31 rolls a 2 and moves to square 33 Player 3 on square 59 rolls a 5 and moves to square 64 Oops! Landed on a snake. Slither down to 60 Player 1 on square 24 rolls a 3 and moves to square 27 Player 2 on square 33 rolls a 5 and moves to square 38 Player 3 on square 60 rolls a 1 and moves to square 61 Player 1 on square 27 rolls a 6 and moves to square 33 Player 2 on square 38 rolls a 3 and moves to square 41 Player 3 on square 61 rolls a 3 and moves to square 64 Oops! Landed on a snake. Slither down to 60 Player 1 on square 33 rolls a 3 and moves to square 36 Player 2 on square 41 rolls a 1 and moves to square 42 Player 3 on square 60 rolls a 4 and moves to square 64 Oops! Landed on a snake. Slither down to 60 Player 1 on square 36 rolls a 2 and moves to square 38 Player 2 on square 42 rolls a 2 and moves to square 44 Player 3 on square 60 rolls a 4 and moves to square 64 Oops! Landed on a snake. Slither down to 60 Player 1 on square 38 rolls a 5 and moves to square 43 Player 2 on square 44 rolls a 6 and moves to square 50 Player 3 on square 60 rolls a 5 and moves to square 65 Player 1 on square 43 rolls a 2 and moves to square 45 Player 2 on square 50 rolls a 3 and moves to square 53 Player 3 on square 65 rolls a 4 and moves to square 69 Player 1 on square 45 rolls a 1 and moves to square 46 Player 2 on square 53 rolls a 4 and moves to square 57 Player 3 on square 69 rolls a 4 and moves to square 73 Player 1 on square 46 rolls a 3 and moves to square 49 Player 2 on square 57 rolls a 6 and moves to square 63 Yay! Landed on a ladder. Climb up to 81 Player 3 on square 73 rolls a 1 and moves to square 74 Player 1 on square 49 rolls a 2 and moves to square 51 Yay! Landed on a ladder. Climb up to 67 Player 2 on square 81 rolls a 4 and moves to square 85 Player 3 on square 74 rolls a 4 and moves to square 78 Player 1 on square 67 rolls a 3 and moves to square 70 Player 2 on square 85 rolls a 4 and moves to square 89 Player 3 on square 78 rolls a 4 and moves to square 82 Player 1 on square 70 rolls a 3 and moves to square 73 Player 2 on square 89 rolls a 3 and moves to square 92 Player 3 on square 82 rolls a 3 and moves to square 85 Player 1 on square 73 rolls a 3 and moves to square 76 Player 2 on square 92 rolls a 2 and moves to square 94 Player 3 on square 85 rolls a 5 and moves to square 90 Player 1 on square 76 rolls a 4 and moves to square 80 Player 2 on square 94 rolls a 6 and moves to square 100 Player 2 wins!

## FreeBASIC

```
Dim Shared As Integer SNL(1 To 16, 1 To 2) => {_
{ 4, 14}, { 9, 31}, {17, 7}, {20, 38}, {28, 84}, {40, 59}, {51, 67}, {54, 34}, _
{62, 19}, {63, 81}, {64, 60}, {71, 91}, {87, 24}, {93, 73}, {95, 75}, {99, 78}}
Randomize Timer
Const sixesThrowAgain = True
Function Turn(player As Integer, square As Integer) As Integer
Do
Dim As Integer roll = Int(Rnd * 6) + 1
Print "Player"; player; ", on square"; square; ", rolls a"; roll;
If square + roll > 100 Then
Print " but cannot move."
Else
square += roll
Print " and moves to square"; square
If square = 100 Then Return 100 : End If
Dim As Integer nxt = square
If SNL(square, square) Then nxt = SNL(nxt, nxt) : End If
If square < nxt Then
Print "Yay! Landed on a ladder. Climb up to"; nxt; "."
If nxt = 100 Then Return 100 : End If
square = nxt
Elseif square > nxt Then
Print "Oops! Landed on a snake. Slither down to"; nxt; "."
square = nxt
End If
End If
If roll < 6 Orelse Not sixesThrowAgain Then Return square : End If
Print "Rolled a 6 so roll again."
Loop
End Function
Dim As Integer players(3) = {1, 1, 1}
Do
For i As Integer = 1 To Ubound(players)
Dim As Integer ns = Turn(i, players(i - 1))
If ns = 100 Then
Print "Player"; i; " wins!"
Exit Do
End If
players(i - 1) = ns
Print
Next i
Loop
Sleep
```

## Go

```
package main
import (
"fmt"
"math/rand"
"time"
)
var snl = map[int]int{
4: 14, 9: 31, 17: 7, 20: 38, 28: 84, 40: 59, 51: 67, 54: 34,
62: 19, 63: 81, 64: 60, 71: 91, 87: 24, 93: 73, 95: 75, 99: 78,
}
const sixThrowsAgain = true
func turn(player, square int) int {
for {
roll := 1 + rand.Intn(6)
fmt.Printf("Player %d, on square %d, rolls a %d", player, square, roll)
if square+roll > 100 {
fmt.Println(" but cannot move.")
} else {
square += roll
fmt.Printf(" and moves to square %d.\n", square)
if square == 100 {
return 100
}
next, ok := snl[square]
if !ok {
next = square
}
if square < next {
fmt.Printf("Yay! Landed on a ladder. Climb up to %d.\n", next)
if next == 100 {
return 100
}
square = next
} else if square > next {
fmt.Printf("Oops! Landed on a snake. Slither down to %d.\n", next)
square = next
}
}
if roll < 6 || !sixThrowsAgain {
return square
}
fmt.Println("Rolled a 6 so roll again.")
}
}
func main() {
rand.Seed(time.Now().UnixNano())
// three players starting on square one
players := [3]int{1, 1, 1}
for {
for i, s := range players {
ns := turn(i+1, s)
if ns == 100 {
fmt.Println("Player", i+1, "wins!")
return
}
players[i] = ns
fmt.Println()
}
}
}
```

Sample game:

Player 1, on square 1, rolls a 3 and moves to square 4. Yay! Landed on a ladder. Climb up to 14. Player 2, on square 1, rolls a 2 and moves to square 3. Player 3, on square 1, rolls a 3 and moves to square 4. Yay! Landed on a ladder. Climb up to 14. Player 1, on square 14, rolls a 5 and moves to square 19. Player 2, on square 3, rolls a 2 and moves to square 5. Player 3, on square 14, rolls a 4 and moves to square 18. Player 1, on square 19, rolls a 5 and moves to square 24. Player 2, on square 5, rolls a 1 and moves to square 6. Player 3, on square 18, rolls a 3 and moves to square 21. Player 1, on square 24, rolls a 1 and moves to square 25. Player 2, on square 6, rolls a 4 and moves to square 10. Player 3, on square 21, rolls a 6 and moves to square 27. Rolled a 6 so roll again. Player 3, on square 27, rolls a 6 and moves to square 33. Rolled a 6 so roll again. Player 3, on square 33, rolls a 4 and moves to square 37. Player 1, on square 25, rolls a 5 and moves to square 30. Player 2, on square 10, rolls a 4 and moves to square 14. Player 3, on square 37, rolls a 5 and moves to square 42. Player 1, on square 30, rolls a 5 and moves to square 35. Player 2, on square 14, rolls a 3 and moves to square 17. Oops! Landed on a snake. Slither down to 7. Player 3, on square 42, rolls a 5 and moves to square 47. Player 1, on square 35, rolls a 5 and moves to square 40. Yay! Landed on a ladder. Climb up to 59. Player 2, on square 7, rolls a 5 and moves to square 12. Player 3, on square 47, rolls a 6 and moves to square 53. Rolled a 6 so roll again. Player 3, on square 53, rolls a 6 and moves to square 59. Rolled a 6 so roll again. Player 3, on square 59, rolls a 3 and moves to square 62. Oops! Landed on a snake. Slither down to 19. Player 1, on square 59, rolls a 2 and moves to square 61. Player 2, on square 12, rolls a 4 and moves to square 16. Player 3, on square 19, rolls a 6 and moves to square 25. Rolled a 6 so roll again. Player 3, on square 25, rolls a 4 and moves to square 29. Player 1, on square 61, rolls a 2 and moves to square 63. Yay! Landed on a ladder. Climb up to 81. Player 2, on square 16, rolls a 5 and moves to square 21. Player 3, on square 29, rolls a 3 and moves to square 32. Player 1, on square 81, rolls a 5 and moves to square 86. Player 2, on square 21, rolls a 3 and moves to square 24. Player 3, on square 32, rolls a 4 and moves to square 36. Player 1, on square 86, rolls a 4 and moves to square 90. Player 2, on square 24, rolls a 6 and moves to square 30. Rolled a 6 so roll again. Player 2, on square 30, rolls a 3 and moves to square 33. Player 3, on square 36, rolls a 1 and moves to square 37. Player 1, on square 90, rolls a 5 and moves to square 95. Oops! Landed on a snake. Slither down to 75. Player 2, on square 33, rolls a 1 and moves to square 34. Player 3, on square 37, rolls a 3 and moves to square 40. Yay! Landed on a ladder. Climb up to 59. Player 1, on square 75, rolls a 5 and moves to square 80. Player 2, on square 34, rolls a 5 and moves to square 39. Player 3, on square 59, rolls a 3 and moves to square 62. Oops! Landed on a snake. Slither down to 19. Player 1, on square 80, rolls a 4 and moves to square 84. Player 2, on square 39, rolls a 3 and moves to square 42. Player 3, on square 19, rolls a 1 and moves to square 20. Yay! Landed on a ladder. Climb up to 38. Player 1, on square 84, rolls a 5 and moves to square 89. Player 2, on square 42, rolls a 2 and moves to square 44. Player 3, on square 38, rolls a 1 and moves to square 39. Player 1, on square 89, rolls a 4 and moves to square 93. Oops! Landed on a snake. Slither down to 73. Player 2, on square 44, rolls a 4 and moves to square 48. Player 3, on square 39, rolls a 1 and moves to square 40. Yay! Landed on a ladder. Climb up to 59. Player 1, on square 73, rolls a 3 and moves to square 76. Player 2, on square 48, rolls a 2 and moves to square 50. Player 3, on square 59, rolls a 1 and moves to square 60. Player 1, on square 76, rolls a 2 and moves to square 78. Player 2, on square 50, rolls a 2 and moves to square 52. Player 3, on square 60, rolls a 4 and moves to square 64. Oops! Landed on a snake. Slither down to 60. Player 1, on square 78, rolls a 5 and moves to square 83. Player 2, on square 52, rolls a 2 and moves to square 54. Oops! Landed on a snake. Slither down to 34. Player 3, on square 60, rolls a 4 and moves to square 64. Oops! Landed on a snake. Slither down to 60. Player 1, on square 83, rolls a 1 and moves to square 84. Player 2, on square 34, rolls a 2 and moves to square 36. Player 3, on square 60, rolls a 3 and moves to square 63. Yay! Landed on a ladder. Climb up to 81. Player 1, on square 84, rolls a 1 and moves to square 85. Player 2, on square 36, rolls a 4 and moves to square 40. Yay! Landed on a ladder. Climb up to 59. Player 3, on square 81, rolls a 5 and moves to square 86. Player 1, on square 85, rolls a 5 and moves to square 90. Player 2, on square 59, rolls a 4 and moves to square 63. Yay! Landed on a ladder. Climb up to 81. Player 3, on square 86, rolls a 3 and moves to square 89. Player 1, on square 90, rolls a 2 and moves to square 92. Player 2, on square 81, rolls a 3 and moves to square 84. Player 3, on square 89, rolls a 2 and moves to square 91. Player 1, on square 92, rolls a 3 and moves to square 95. Oops! Landed on a snake. Slither down to 75. Player 2, on square 84, rolls a 2 and moves to square 86. Player 3, on square 91, rolls a 6 and moves to square 97. Rolled a 6 so roll again. Player 3, on square 97, rolls a 3 and moves to square 100. Player 3 wins!

## J

**Solution**

As discussed in other implementations, this game is purely determined by chance and no user input is actually required.

The following game starts with players' counters off the board, an exact roll is not required to win and no additional dice roll results from throwing a six.

```
require 'format/printf general/misc/prompt'
SnakesLadders=: _2 ]\ 4 14 9 31 17 7 20 38 28 84 40 59 51 67 54 34 62 19 63 81 64 60 71 91 87 24 93 73 95 75 99 78
'idx val'=: |: SnakesLadders
Board=: val idx} i. >: 100 NB. representation of the board
rollDice=: 1 + $ ?@$ 6: NB. roll dice once for each player
playTurn=: Board {~ 100 <. rollDice + ] NB. returns list of new posisitions given a list of starting positions
NB. Given the number of players, runs until one player reaches 100
runGame=: [: playTurn^:(100 -.@e. ])^:(<_) $&0
NB. Report player positions after each turn and result
report=: ('Player %d won!' sprintf 100 >:@i.~ {:) , echo
start=: >:@".@prompt&'How many players to play against?' [ echo bind 'You are Player 1!'
playSnakesLadders=: [: report@runGame start
```

**Example Usage:**

```
playSnakesLadders''
You are Player 1!
How many players to play against?
4
0 0 0 0 0
5 5 5 5 6
7 31 11 8 8
13 35 16 14 10
14 36 7 18 11
38 42 31 21 14
39 46 35 25 15
41 48 37 84 7
42 34 41 90 8
47 39 43 96 31
50 59 48 78 37
56 60 34 81 39
59 61 39 84 41
60 67 43 88 44
60 73 44 94 45
61 79 50 100 49
Player 4 won!
```

## Java

```
import java.util.Map;
import java.util.Random;
public class Game {
private static final Map<Integer, Integer> snl = Map.ofEntries(
Map.entry(4, 14),
Map.entry(9, 31),
Map.entry(17, 7),
Map.entry(20, 38),
Map.entry(28, 84),
Map.entry(40, 59),
Map.entry(51, 67),
Map.entry(54, 34),
Map.entry(62, 19),
Map.entry(63, 81),
Map.entry(64, 60),
Map.entry(71, 91),
Map.entry(87, 24),
Map.entry(93, 73),
Map.entry(95, 75),
Map.entry(99, 78)
);
private static final boolean sixesThrowAgain = true;
private static Random rand = new Random();
private static int turn(int player, int square) {
int square2 = square;
while (true) {
int roll = rand.nextInt(6) + 1;
System.out.printf("Player %d, on square %d, rolls a %d", player, square2, roll);
if (square2 + roll > 100) {
System.out.println(" but cannot move.");
} else {
square2 += roll;
System.out.printf(" and moves to square %d\n", square2);
if (square2 == 100) return 100;
Integer next = snl.getOrDefault(square2, square2);
if (square2 < next) {
System.out.printf("Yay! Landed on a ladder. Climb up to %d.\n", next);
if (next == 100) return 100;
square2 = next;
} else if (square2 > next) {
System.out.printf("Oops! Landed on a snake. Slither down to %d.\n", next);
square2 = next;
}
}
if (roll < 6 || !sixesThrowAgain) return square2;
System.out.println("Rolled a 6 so roll again.");
}
}
public static void main(String[] args) {
// three players starting on square one
int[] players = {1, 1, 1};
while (true) {
for (int i = 0; i < players.length; ++i) {
int ns = turn(i + 1, players[i]);
if (ns == 100) {
System.out.printf("Player %d wins!\n", i + 1);
return;
}
players[i] = ns;
System.out.println();
}
}
}
}
```

## Julia

The game is pure chance, with a 2% advantage to going before the next player. See statistics below.

```
const landingtoending = Dict(4 => 14, 9 => 31, 17 => 7, 20 => 38, 28 => 84, 40 => 59,
51 => 67, 54 => 34, 62 => 19, 63 => 81, 64 => 60, 71 => 91, 87 => 24, 93 => 73,
95 => 75, 99 => 78)
const sixesrollagain = true
function takeaturn(player, square, verbose=true)
while true
roll = rand(1:6)
verbose && print("Player $player on square $square rolls a $roll ")
if square + roll > 100
verbose && println(" but cannot move.")
else
square += roll
verbose && println(" and moves to square $square.")
if square == 100
return 100
end
next = get(landingtoending, square, square)
if square < next
verbose && println("Yay! landed on a ladder. Climb up to $next.")
if square == 100
return 100
end
square = next
elseif square > next
verbose && println("Oops! Landed on a snake chute. Slither down to $next.")
square = next
end
end
if roll < 6 || !sixesrollagain
return square
else
verbose && println("Rolled a 6, so roll again.")
end
end
end
function snakesandladdersgame(nplayers, verbose=true)
players = ones(Int, nplayers)
while true
for (player, position) in enumerate(players)
ns = takeaturn(player, position, verbose)
if ns == 100
verbose && println("Player $player wins!")
return player
end
players[player] = ns
verbose && println()
end
end
end
snakesandladdersgame(3)
using DataFrames, GLM
function slstats(nplayers, ngames)
players = zeros(Int, nplayers)
for i in 1:ngames
winner = snakesandladdersgame(nplayers, false)
players[winner] += 1
end
println("\n\n\nStats: out of $ngames games, winners by order of play are:\n # | wins \n----------------")
for (i, player) in enumerate(players)
println(" $i $player")
end
data = DataFrame(X = collect(1:nplayers), Y = players)
ols = lm(@formula(Y ~ X), data)
println("\nStatistics:\n", ols)
end
slstats(5, 1000000)
```

- Output:

Player 1 on square 1 rolls a 5 and moves to square 6. Player 2 on square 1 rolls a 3 and moves to square 4. Yay! landed on a ladder. Climb up to 14. Player 3 on square 1 rolls a 5 and moves to square 6. Player 1 on square 6 rolls a 1 and moves to square 7. Player 2 on square 14 rolls a 5 and moves to square 19. Player 3 on square 6 rolls a 5 and moves to square 11. Player 1 on square 7 rolls a 2 and moves to square 9. Yay! landed on a ladder. Climb up to 31. Player 2 on square 19 rolls a 3 and moves to square 22. Player 3 on square 11 rolls a 3 and moves to square 14. Player 1 on square 31 rolls a 5 and moves to square 36. Player 2 on square 22 rolls a 3 and moves to square 25. Player 3 on square 14 rolls a 4 and moves to square 18. Player 1 on square 36 rolls a 6 and moves to square 42. Rolled a 6, so roll again. Player 1 on square 42 rolls a 6 and moves to square 48. Rolled a 6, so roll again. Player 1 on square 48 rolls a 3 and moves to square 51. Yay! landed on a ladder. Climb up to 67. Player 2 on square 25 rolls a 2 and moves to square 27. Player 3 on square 18 rolls a 3 and moves to square 21. Player 1 on square 67 rolls a 1 and moves to square 68. Player 2 on square 27 rolls a 1 and moves to square 28. Yay! landed on a ladder. Climb up to 84. Player 3 on square 21 rolls a 6 and moves to square 27. Rolled a 6, so roll again. Player 3 on square 27 rolls a 5 and moves to square 32. Player 1 on square 68 rolls a 3 and moves to square 71. Yay! landed on a ladder. Climb up to 91. Player 2 on square 84 rolls a 5 and moves to square 89. Player 3 on square 32 rolls a 2 and moves to square 34. Player 1 on square 91 rolls a 6 and moves to square 97. Rolled a 6, so roll again. Player 1 on square 97 rolls a 5 but cannot move. Player 2 on square 89 rolls a 4 and moves to square 93. Oops! Landed on a snake chute. Slither down to 73. Player 3 on square 34 rolls a 1 and moves to square 35. Player 1 on square 97 rolls a 3 and moves to square 100. Player 1 wins! Stats: out of 1000000 games, winners by order of play are: # | wins ---------------- 1 208036 2 204760 3 199392 4 195319 5 192493 Statistics: StatsModels.TableRegressionModel{LinearModel{GLM.LmResp{Array{Float64,1}},GLM.DensePredChol{Float64,LinearAlgebra.Cholesky{Float64,Array{Float64,2}}}},Array{Float64,2}} Y ~ 1 + X Coefficients: ────────────────────────────────────────────────────────────────────────────────────── Estimate Std. Error t value Pr(>|t|) Lower 95% Upper 95% ────────────────────────────────────────────────────────────────────────────────────── (Intercept) 2.12158e5 772.519 274.632 <1e-6 2.097e5 2.14617e5 X -4052.7 232.923 -17.3993 0.0004 -4793.97 -3311.43 ──────────────────────────────────────────────────────────────────────────────────────

## Kotlin

This includes an option for the player to automatically roll again when a six is rolled which I believe is a common variation:

```
// version 1.2.0
import java.util.Random
val rand = Random()
val snl = mapOf(
4 to 14, 9 to 31, 17 to 7, 20 to 38, 28 to 84, 40 to 59, 51 to 67, 54 to 34,
62 to 19, 63 to 81, 64 to 60, 71 to 91, 87 to 24, 93 to 73, 95 to 75, 99 to 78
)
val sixThrowsAgain = true
fun turn(player: Int, square: Int): Int {
var square2 = square
while (true) {
val roll = 1 + rand.nextInt(6)
print("Player $player, on square $square2, rolls a $roll")
if (square2 + roll > 100) {
println(" but cannot move.")
}
else {
square2 += roll
println(" and moves to square $square2.")
if (square2 == 100) return 100
val next = snl.getOrDefault(square2, square2)
if (square2 < next) {
println("Yay! Landed on a ladder. Climb up to $next.")
if (next == 100) return 100
square2 = next
}
else if (square2 > next) {
println("Oops! Landed on a snake. Slither down to $next.")
square2 = next
}
}
if (roll < 6 || !sixThrowsAgain) return square2
println("Rolled a 6 so roll again.")
}
}
fun main(args: Array<String>) {
// three players starting on square one
val players = intArrayOf(1, 1, 1)
while (true) {
for ((i, s) in players.withIndex()) {
val ns = turn(i + 1, s)
if (ns == 100) {
println("Player ${i+1} wins!")
return
}
players[i] = ns
println()
}
}
}
```

Sample output:

Player 1, on square 1, rolls a 1 and moves to square 2. Player 2, on square 1, rolls a 3 and moves to square 4. Yay! Landed on a ladder. Climb up to 14. Player 3, on square 1, rolls a 6 and moves to square 7. Rolled a 6 so roll again. Player 3, on square 7, rolls a 3 and moves to square 10. Player 1, on square 2, rolls a 5 and moves to square 7. Player 2, on square 14, rolls a 4 and moves to square 18. Player 3, on square 10, rolls a 5 and moves to square 15. Player 1, on square 7, rolls a 3 and moves to square 10. Player 2, on square 18, rolls a 1 and moves to square 19. Player 3, on square 15, rolls a 1 and moves to square 16. Player 1, on square 10, rolls a 2 and moves to square 12. Player 2, on square 19, rolls a 5 and moves to square 24. Player 3, on square 16, rolls a 2 and moves to square 18. Player 1, on square 12, rolls a 2 and moves to square 14. Player 2, on square 24, rolls a 6 and moves to square 30. Rolled a 6 so roll again. Player 2, on square 30, rolls a 2 and moves to square 32. Player 3, on square 18, rolls a 1 and moves to square 19. Player 1, on square 14, rolls a 6 and moves to square 20. Yay! Landed on a ladder. Climb up to 38. Rolled a 6 so roll again. Player 1, on square 38, rolls a 3 and moves to square 41. Player 2, on square 32, rolls a 4 and moves to square 36. Player 3, on square 19, rolls a 6 and moves to square 25. Rolled a 6 so roll again. Player 3, on square 25, rolls a 3 and moves to square 28. Yay! Landed on a ladder. Climb up to 84. Player 1, on square 41, rolls a 4 and moves to square 45. Player 2, on square 36, rolls a 6 and moves to square 42. Rolled a 6 so roll again. Player 2, on square 42, rolls a 3 and moves to square 45. Player 3, on square 84, rolls a 1 and moves to square 85. Player 1, on square 45, rolls a 1 and moves to square 46. Player 2, on square 45, rolls a 1 and moves to square 46. Player 3, on square 85, rolls a 5 and moves to square 90. Player 1, on square 46, rolls a 1 and moves to square 47. Player 2, on square 46, rolls a 5 and moves to square 51. Yay! Landed on a ladder. Climb up to 67. Player 3, on square 90, rolls a 4 and moves to square 94. Player 1, on square 47, rolls a 4 and moves to square 51. Yay! Landed on a ladder. Climb up to 67. Player 2, on square 67, rolls a 1 and moves to square 68. Player 3, on square 94, rolls a 4 and moves to square 98. Player 1, on square 67, rolls a 5 and moves to square 72. Player 2, on square 68, rolls a 3 and moves to square 71. Yay! Landed on a ladder. Climb up to 91. Player 3, on square 98, rolls a 3 but cannot move. Player 1, on square 72, rolls a 1 and moves to square 73. Player 2, on square 91, rolls a 4 and moves to square 95. Oops! Landed on a snake. Slither down to 75. Player 3, on square 98, rolls a 6 but cannot move. Rolled a 6 so roll again. Player 3, on square 98, rolls a 6 but cannot move. Rolled a 6 so roll again. Player 3, on square 98, rolls a 2 and moves to square 100. Player 3 wins!

## Lua

```
local sixesThrowAgain = true
function rollDice()
return math.random(6)
end
function nextSquare(square)
if square == 4 then
return 14
elseif square == 9 then
return 31
elseif square == 17 then
return 7
elseif square == 20 then
return 38
elseif square == 28 then
return 84
elseif square == 40 then
return 59
elseif square == 51 then
return 67
elseif square == 54 then
return 34
elseif square == 62 then
return 19
elseif square == 63 then
return 81
elseif square == 64 then
return 60
elseif square == 71 then
return 91
elseif square == 87 then
return 24
elseif square == 93 then
return 73
elseif square == 95 then
return 75
elseif square == 99 then
return 78
else
return square
end
end
function turn(player, square)
while true do
local roll = rollDice()
io.write(string.format("Player %d, on square %d, rolls a %d", player, square, roll))
if square + roll > 100 then
io.write(" but cannot move.\n")
else
square = square + roll
io.write(string.format(" and moves to square %d\n", square))
if square == 100 then
return 100
end
local nxt = nextSquare(square)
if square < nxt then
io.write(string.format("Yay! Landed on a ladder. Climb up to %d\n", square))
square = nxt
elseif nxt < square then
io.write(string.format("Oops! Landed on a snake. Slither down to %d\n", square))
square = nxt
end
end
if roll < 6 or not sizexThrowAgain then
return square
end
io.write("Rolled a 6 so roll again.\n")
end
end
function main()
local players = {1, 1, 1}
while true do
for i=1,3 do
local ns = turn(i, players[i])
if ns == 100 then
io.write(string.format("Player %d wins!\n", i))
return
end
players[i] = ns
print()
end
end
end
main()
```

## Modula-2

```
MODULE SnakeAndLadder;
FROM FormatString IMPORT FormatString;
FROM RandomNumbers IMPORT Random;
FROM Terminal IMPORT WriteString,WriteLn,ReadChar;
CONST SIXES_THROW_AGAIN = TRUE;
PROCEDURE NextSquare(sq : CARDINAL) : CARDINAL;
BEGIN
(* Emulate a map for the ladders and snakes *)
IF sq = 4 THEN RETURN 14
ELSIF sq = 9 THEN RETURN 31
ELSIF sq = 17 THEN RETURN 7
ELSIF sq = 20 THEN RETURN 38
ELSIF sq = 28 THEN RETURN 84
ELSIF sq = 40 THEN RETURN 59
ELSIF sq = 51 THEN RETURN 67
ELSIF sq = 54 THEN RETURN 34
ELSIF sq = 62 THEN RETURN 19
ELSIF sq = 63 THEN RETURN 81
ELSIF sq = 64 THEN RETURN 60
ELSIF sq = 71 THEN RETURN 91
ELSIF sq = 87 THEN RETURN 24
ELSIF sq = 93 THEN RETURN 73
ELSIF sq = 95 THEN RETURN 75
ELSIF sq = 99 THEN RETURN 78
END;
(* No snakes or ladders encountered *)
RETURN sq
END NextSquare;
PROCEDURE Turn(player,square : CARDINAL) : CARDINAL;
VAR
buf : ARRAY[0..63] OF CHAR;
roll,next : CARDINAL;
BEGIN
LOOP
roll := Random(1,6);
FormatString("Player %c, on square %c, rolls a %c", buf, player, square, roll);
WriteString(buf);
IF square + roll > 100 THEN
WriteString(" but cannot move.");
WriteLn
ELSE
square := square + roll;
FormatString(" and moves to square %c\n", buf, square);
WriteString(buf);
IF square = 100 THEN RETURN 100 END;
next := NextSquare(square);
IF square < next THEN
FormatString("Yay! Landed on a ladder. Climb up to %c.\n", buf, next);
WriteString(buf);
IF next = 100 THEN RETURN 100 END;
square := next
ELSIF square > next THEN
FormatString("Oops! Landed on a snake. Slither down to %c.\n", buf, next);
WriteString(buf);
IF next = 100 THEN RETURN 100 END;
square := next
END
END;
IF (roll < 6) OR NOT SIXES_THROW_AGAIN THEN RETURN square END;
WriteString("Rolled a 6 so roll again.");
WriteLn
END;
RETURN square
END Turn;
(* Main *)
VAR
buf : ARRAY[0..31] OF CHAR;
players : ARRAY[0..2] OF CARDINAL;
i,ns : CARDINAL;
BEGIN
(* Initialize *)
FOR i:=0 TO HIGH(players) DO
players[i] := 1
END;
(* Game play *)
LOOP
FOR i:=0 TO HIGH(players) DO
ns := Turn(i+1, players[i]);
IF ns = 100 THEN
FormatString("Player %c wins!\n", buf, i+1);
WriteString(buf);
EXIT
END;
players[i] := ns;
WriteLn
END
END;
ReadChar
END SnakeAndLadder.
```

## Nim

```
import random, sequtils, strformat, tables
const Snl = {4: 14, 9: 31, 17: 7, 20: 38, 28: 84, 40: 59, 51: 67, 54: 34,
62: 19, 63: 81, 64: 60, 71: 91, 87: 24, 93: 73, 95: 75, 99: 78}.toTable
const SixThrowsAgain = true
proc turn(player, square: Positive): int =
var square = square
while true:
let roll = rand(1..6)
stdout.write &"Player {player}, on square {square}, rolls a {roll}"
if square + roll > 100:
echo " but cannot move."
else:
inc square, roll
echo &" and moves to square {square}."
if square == 100: return 100
let next = Snl.getOrDefault(square, square)
if square < next:
echo &"Yay! Landed on a ladder. Climb up to {next}."
if next == 100: return 100
square = next
elif square > next:
echo &"Oops! Landed on a snake. Slither down to {next}."
square = next
if roll < 6 or not SixThrowsAgain: return square
echo "Rolled a 6 so roll again."
proc playGame(n: Positive) =
# "n" players starting on square one.
var players = repeat(1, n)
while true:
for i, s in players:
let ns = turn(i + 1, s)
if ns == 100:
echo &"Player {i+1} wins!"
return
players[i] = ns
echo()
randomize()
when isMainModule:
playGame(3)
```

- Output:

Sample game.

Player 1, on square 1, rolls a 4 and moves to square 5. Player 2, on square 1, rolls a 5 and moves to square 6. Player 3, on square 1, rolls a 2 and moves to square 3. Player 1, on square 5, rolls a 5 and moves to square 10. Player 2, on square 6, rolls a 3 and moves to square 9. Yay! Landed on a ladder. Climb up to 31. Player 3, on square 3, rolls a 5 and moves to square 8. Player 1, on square 10, rolls a 1 and moves to square 11. Player 2, on square 31, rolls a 3 and moves to square 34. Player 3, on square 8, rolls a 1 and moves to square 9. Yay! Landed on a ladder. Climb up to 31. Player 1, on square 11, rolls a 1 and moves to square 12. Player 2, on square 34, rolls a 2 and moves to square 36. Player 3, on square 31, rolls a 1 and moves to square 32. Player 1, on square 12, rolls a 1 and moves to square 13. Player 2, on square 36, rolls a 6 and moves to square 42. Rolled a 6 so roll again. Player 2, on square 42, rolls a 5 and moves to square 47. Player 3, on square 32, rolls a 2 and moves to square 34. Player 1, on square 13, rolls a 6 and moves to square 19. Rolled a 6 so roll again. Player 1, on square 19, rolls a 5 and moves to square 24. Player 2, on square 47, rolls a 1 and moves to square 48. Player 3, on square 34, rolls a 6 and moves to square 40. Yay! Landed on a ladder. Climb up to 59. Rolled a 6 so roll again. Player 3, on square 59, rolls a 1 and moves to square 60. Player 1, on square 24, rolls a 5 and moves to square 29. Player 2, on square 48, rolls a 1 and moves to square 49. Player 3, on square 60, rolls a 4 and moves to square 64. Oops! Landed on a snake. Slither down to 60. Player 1, on square 29, rolls a 1 and moves to square 30. Player 2, on square 49, rolls a 2 and moves to square 51. Yay! Landed on a ladder. Climb up to 67. Player 3, on square 60, rolls a 6 and moves to square 66. Rolled a 6 so roll again. Player 3, on square 66, rolls a 5 and moves to square 71. Yay! Landed on a ladder. Climb up to 91. Player 1, on square 30, rolls a 1 and moves to square 31. Player 2, on square 67, rolls a 5 and moves to square 72. Player 3, on square 91, rolls a 3 and moves to square 94. Player 1, on square 31, rolls a 3 and moves to square 34. Player 2, on square 72, rolls a 1 and moves to square 73. Player 3, on square 94, rolls a 2 and moves to square 96. Player 1, on square 34, rolls a 6 and moves to square 40. Yay! Landed on a ladder. Climb up to 59. Rolled a 6 so roll again. Player 1, on square 59, rolls a 2 and moves to square 61. Player 2, on square 73, rolls a 2 and moves to square 75. Player 3, on square 96, rolls a 4 and moves to square 100. Player 3 wins!

## Perl

```
# board layout
my %snl =( 4, 14, 9, 31, 17, 7, 20, 38, 28, 84, 40, 59, 51, 67, 54, 34,
62, 19, 63, 81, 64, 60, 71, 91, 87, 24, 93, 73, 95, 75, 99, 78);
@players = (1, 1, 1, 1); # 4 players, starting on square 1 (last player is human)
while () {
for $player (0..$#players) {
$turn_count++;
turn(\$players[$player], $player + 1, $turn_count);
}
}
sub turn {
my($square, $player) = @_;
if ($player == @players) { print "You are on square $$square. Hit enter to roll the die:"; <> }
my $roll = 1 + int rand 6;
my $turn = $$square + $roll;
print "Player $player on square %2d rolls a $roll", $$square;
if ($turn > 100) {
print " but cannot move. Next players turn.\n";
return
}
if ($snl{$turn}) {
$$square = $snl{$turn};
if ($turn > $$square) {
print ". Oops! Landed on a snake. Slither down to $$square.\n"
} else {
print ". Yay! Landed on a ladder. Climb up to $$square.\n"
}
} else {
$$square = $turn;
print " and moves to square $$square\n";
}
if ($$square == 100) {print "Player $player wins after $turn_count turns.\n"; exit }
return
}
```

- Output:

Player 1 on square 1 rolls a 3. Yay! Landed on a ladder. Climb up to 14. Player 2 on square 1 rolls a 1 and moves to square 2 Player 3 on square 1 rolls a 5 and moves to square 6 Player 4 on square 1 rolls a 4 and moves to square 5 Player 1 on square 14 rolls a 6. Yay! Landed on a ladder. Climb up to 38. Player 2 on square 2 rolls a 2. Yay! Landed on a ladder. Climb up to 14. Player 3 on square 6 rolls a 4 and moves to square 10 Player 4 on square 5 rolls a 3 and moves to square 8 ... 703 turns omitted ... Player 1 on square 83 rolls a 1 and moves to square 84 Player 2 on square 98 rolls a 2 and moves to square 100 Player 2 wins after 706 turns.

## Phix

with javascript_semantics constant sixesThrowAgain = true constant snl = new_dict({{4,14},{9,31},{17,7},{20,38},{28,84},{40,59},{51,67},{54,34}, {62,19},{63,81},{64,60},{71,91},{87,24},{93,73},{95,75},{99,78}}) constant msgs = {". Oops! Landed on a snake. Slither down to %d.\n", -- (next<square) " and moves to square %d\n", -- (next=square) ". Yay! Landed on a ladder. Climb up to %d.\n"} -- (next>square) function Turn(integer player, square) while true do integer roll = rand(6) printf(1,"Player %d, on square %d, rolls a %d", {player, square, roll}) if square+roll>100 then puts(1," but cannot move.\n") else square += roll integer next = getd(square,snl) if next=0 then next=square end if printf(1,msgs[compare(next,square)+2],next) square = next if square==100 then exit end if end if if roll<6 or not sixesThrowAgain then exit end if puts(1,"Rolled a 6 so roll again.\n") end while return square end function procedure main() sequence players = {1,1,1} -- three players starting on square one while true do for i=1 to length(players) do players[i] = Turn(i, players[i]) if players[i]==100 then printf(1,"Player %d wins!\n",i) return end if end for end while end procedure main()

- Output:

Player 1, on square 1, rolls a 2 and moves to square 3 Player 2, on square 1, rolls a 1 and moves to square 2 Player 3, on square 1, rolls a 3. Yay! Landed on a ladder. Climb up to 14. ... Player 3, on square 89, rolls a 5 and moves to square 94 Player 1, on square 90, rolls a 3. Oops! Landed on a snake. Slither down to 73. Player 2, on square 97, rolls a 3 and moves to square 100 Player 2 wins!

## PicoLisp

```
(seed (in "/dev/urandom" (rd 8)))
(setq *D
'((4 14 T) (9 31 T) (17 7) (20 38 T)
(28 84 T) (40 59 T) (51 67 T) (54 34)
(62 19) (63 81 T) (64 60) (71 91 T)
(87 24) (93 73) (95 75) (99 78) ) )
(de players (N)
(make
(for I N
(let P (pack "Player " I)
(set P 1)
(link P) ) ) ) )
(de turn (P)
(use D
(loop
(setq D (rand 1 6))
(prin P " on square " (val P) ", rolls a " D)
(if (> (+ (val P) D) 100)
(prinl " but cannot move")
(set P (+ (val P) D))
(prinl " and move to square " (val P))
(when (= (val P) 100)
(prinl P " wins!")
(throw 'win) )
(when (assoc (val P) *D)
(set P (cadr @))
(if (cddr @)
(prinl "Yay! Landed on ladder. Climb up to " (val P))
(prinl "Ooops! Landed on snake. Slither down to " (val P)) ) ) )
(T (> 6 D))
(prinl "Rolled a 6 so roll again") ) ) )
(de main (N)
(let P (players N)
(catch 'win
(loop
(mapc turn P) ) ) ) )
(main 10)
```

- Output:

Player 1 on square 1, rolls a 5 and move to square 6 Player 2 on square 1, rolls a 2 and move to square 3 Player 3 on square 1, rolls a 2 and move to square 3 Player 4 on square 1, rolls a 6 and move to square 7 Rolled a 6 so roll again Player 4 on square 7, rolls a 5 and move to square 12 Player 5 on square 1, rolls a 3 and move to square 4 Yay! Landed on ladder. Climb up to 14 Player 6 on square 1, rolls a 4 and move to square 5 Player 7 on square 1, rolls a 1 and move to square 2 Player 8 on square 1, rolls a 4 and move to square 5 Player 9 on square 1, rolls a 1 and move to square 2 Player 10 on square 1, rolls a 2 and move to square 3 ... ... ... Ooops! Landed on snake. Slither down to 60 Rolled a 6 so roll again Player 9 on square 60, rolls a 6 and move to square 66 Rolled a 6 so roll again Player 9 on square 66, rolls a 2 and move to square 68 Player 10 on square 96, rolls a 4 and move to square 100 Player 10 wins!

## Python

```
import random
import sys
snl = {
4: 14,
9: 31,
17: 7,
20: 38,
28: 84,
40: 59,
51: 67,
54: 34,
62: 19,
63: 81,
64: 60,
71: 91,
87: 24,
93: 73,
95: 75,
99: 78
}
sixesRollAgain = True
def turn(player, square):
while True:
roll = random.randint(1,6)
sys.stdout.write("Player {0} on square {1}, rolls a {2}".format(player, square, roll))
if square + roll > 100:
print " but cannot move."
else:
square += roll
print " and moves to square {0}".format(square)
if square == 100:
return 100
next = snl.get(square, square)
if square < next:
print "Yay! landed on a ladder. Climb up to {0}.".format(next)
if square == 100:
return 100
square = next
elif square > next:
print "Oops! Landed on a snake. Slither down to {0}.".format(next)
square = next
if roll < 6 or not sixesRollAgain:
return square
print "Rolled a 6 so roll again."
def main():
players = [1, 1, 1]
while True:
for i in range(0, 3):
ns = turn(i+1, players[i])
if ns == 100:
print "Player {0} wins!".format(i+1)
return
players[i] = ns;
print
main()
```

## Quackery

```
[ this ] is .. ( --> [ )
[ table 0
.. .. .. 14 .. .. .. .. 31 ..
.. .. .. .. .. .. -7 .. .. 38
.. .. .. .. .. .. .. 84 .. ..
.. .. .. .. .. .. .. .. .. 59
.. .. .. .. .. .. .. .. .. ..
67 .. .. -34 .. .. .. .. .. ..
.. -19 81 -60 .. .. .. .. .. ..
91 .. .. .. .. .. .. .. .. ..
.. .. .. .. .. .. -24 .. .. ..
.. .. -73 .. -75 .. .. .. -78 .. ] is board ( n --> x )
[ $ "What are the player's names? "
input nest$ shuffle
cr say "Order of play: "
dup witheach [ echo$ sp ] cr cr
dup size 0 swap of
false temp put
[ temp share if
[ say "Rolling 6 means the player"
say " receives another go." cr
-1 split swap join
dip [ -1 split swap join ] ]
dip
[ behead dup echo$
nested join ]
behead
say " rolls "
6 random 1+ dup echo
dup 6 = temp replace
2dup + 100 > iff
[ say " which is too many "
say "so they don't move." cr
drop join ]
again
say " and moves to "
+ dup echo
dup 100 = iff
[ say " and wins." cr
drop ]
done
dup board
dup .. = iff
[ drop join
say "." cr ]
again
dup 0 < iff
[ say " which is a snake"
say " so they drop to "
abs dup echo say "." cr
nip join ]
again
say " which is a ladder"
say " so they rise to "
dup echo say "." cr
nip join
again ]
2drop
temp release ] is play ( --> [ )
play
```

- Output:

What are the player's names? Hector Zsazsa Kiki Order of play: Kiki Zsazsa Hector Kiki rolls 6 and moves to 6. Rolling 6 means the player receives another go. Kiki rolls 4 and moves to 10. Zsazsa rolls 5 and moves to 5. Hector rolls 1 and moves to 1. Kiki rolls 2 and moves to 12. Zsazsa rolls 2 and moves to 7. Hector rolls 3 and moves to 4 which is a ladder so they rise to 14. Kiki rolls 3 and moves to 15. Zsazsa rolls 4 and moves to 11. Hector rolls 1 and moves to 15. Kiki rolls 4 and moves to 19. Zsazsa rolls 5 and moves to 16. Hector rolls 1 and moves to 16. Kiki rolls 4 and moves to 23. Zsazsa rolls 4 and moves to 20 which is a ladder so they rise to 38. Hector rolls 2 and moves to 18. Kiki rolls 5 and moves to 28 which is a ladder so they rise to 84. Zsazsa rolls 3 and moves to 41. Hector rolls 6 and moves to 24. Rolling 6 means the player receives another go. Hector rolls 2 and moves to 26. Kiki rolls 3 and moves to 87 which is a snake so they drop to 24. Zsazsa rolls 6 and moves to 47. Rolling 6 means the player receives another go. Zsazsa rolls 5 and moves to 52. Hector rolls 6 and moves to 32. Rolling 6 means the player receives another go. Hector rolls 6 and moves to 38. Rolling 6 means the player receives another go. Hector rolls 3 and moves to 41. Kiki rolls 5 and moves to 29. Zsazsa rolls 5 and moves to 57. Hector rolls 3 and moves to 44. Kiki rolls 2 and moves to 31. Zsazsa rolls 1 and moves to 58. Hector rolls 4 and moves to 48. Kiki rolls 4 and moves to 35. Zsazsa rolls 3 and moves to 61. Hector rolls 4 and moves to 52. Kiki rolls 1 and moves to 36. Zsazsa rolls 3 and moves to 64 which is a snake so they drop to 60. Hector rolls 6 and moves to 58. Rolling 6 means the player receives another go. Hector rolls 4 and moves to 62 which is a snake so they drop to 19. Kiki rolls 4 and moves to 40 which is a ladder so they rise to 59. Zsazsa rolls 6 and moves to 66. Rolling 6 means the player receives another go. Zsazsa rolls 6 and moves to 72. Rolling 6 means the player receives another go. Zsazsa rolls 4 and moves to 76. Hector rolls 4 and moves to 23. Kiki rolls 3 and moves to 62 which is a snake so they drop to 19. Zsazsa rolls 3 and moves to 79. Hector rolls 3 and moves to 26. Kiki rolls 6 and moves to 25. Rolling 6 means the player receives another go. Kiki rolls 2 and moves to 27. Zsazsa rolls 4 and moves to 83. Hector rolls 6 and moves to 32. Rolling 6 means the player receives another go. Hector rolls 6 and moves to 38. Rolling 6 means the player receives another go. Hector rolls 6 and moves to 44. Rolling 6 means the player receives another go. Hector rolls 1 and moves to 45. Kiki rolls 2 and moves to 29. Zsazsa rolls 2 and moves to 85. Hector rolls 6 and moves to 51 which is a ladder so they rise to 67. Rolling 6 means the player receives another go. Hector rolls 1 and moves to 68. Kiki rolls 2 and moves to 31. Zsazsa rolls 3 and moves to 88. Hector rolls 6 and moves to 74. Rolling 6 means the player receives another go. Hector rolls 4 and moves to 78. Kiki rolls 6 and moves to 37. Rolling 6 means the player receives another go. Kiki rolls 1 and moves to 38. Zsazsa rolls 3 and moves to 91. Hector rolls 5 and moves to 83. Kiki rolls 3 and moves to 41. Zsazsa rolls 4 and moves to 95 which is a snake so they drop to 75. Hector rolls 6 and moves to 89. Rolling 6 means the player receives another go. Hector rolls 5 and moves to 94. Kiki rolls 4 and moves to 45. Zsazsa rolls 6 and moves to 81. Rolling 6 means the player receives another go. Zsazsa rolls 3 and moves to 84. Hector rolls 3 and moves to 97. Kiki rolls 1 and moves to 46. Zsazsa rolls 6 and moves to 90. Rolling 6 means the player receives another go. Zsazsa rolls 6 and moves to 96. Rolling 6 means the player receives another go. Zsazsa rolls 1 and moves to 97. Hector rolls 6 which is too many so they don't move. Rolling 6 means the player receives another go. Hector rolls 2 and moves to 99 which is a snake so they drop to 78. Kiki rolls 4 and moves to 50. Zsazsa rolls 5 which is too many so they don't move. Hector rolls 1 and moves to 79. Kiki rolls 2 and moves to 52. Zsazsa rolls 3 and moves to 100 and wins.

## Racket

```
#lang racket/base
(define portals (hash 4 14 9 31 17 7 20 38 28 84 40 59 51 67 54 34 62 19 63 81 64 60 71 91 87 24 93 73 95 75 99 78))
(define (find-game-winner n-players reroll-on-six? (win values))
(let turn ((positions-map (for/hash ((p n-players)) (values p 1))) (player 0))
(newline)
(let ((die (add1 (random 6)))
(position (hash-ref positions-map player)))
(printf "player ~a at ~a rolls ~a: " (add1 player) position die)
(let* ((try-position (+ position die))
(new-position
(cond [(> try-position 100) (display "player can't move beyond the end.") position]
[(= try-position 100) (display "player wins!") try-position]
[(hash-ref portals try-position #f)
=> (λ (slide-to)
(printf "~a from ~a to ~a." (if (> slide-to try-position) "LADDER" "SNAKE") try-position slide-to)
slide-to)]
[else (printf "landed on ~a." try-position) try-position])))
(if (= new-position 100)
(win (add1 player))
(turn (hash-set positions-map player new-position)
(if (and (= 6 die) reroll-on-six?)
(begin0 player (display " [6] rolls again!"))
(modulo (add1 player) n-players))))))))
(module+ main
(find-game-winner 5 #t (λ (p) (printf "~%~%The winner of the game is player #~a" p))))
```

- Output:

player 1 at 1 rolls 2: landed on 3. player 2 at 1 rolls 3: LADDER from 4 to 14. player 3 at 1 rolls 6: landed on 7. [6] rolls again! player 3 at 7 rolls 4: landed on 11. player 4 at 1 rolls 3: LADDER from 4 to 14. player 5 at 1 rolls 5: landed on 6. player 1 at 3 rolls 1: LADDER from 4 to 14. player 2 at 14 rolls 3: SNAKE from 17 to 7. player 3 at 11 rolls 4: landed on 15. ... player 3 at 86 rolls 5: landed on 91. player 4 at 85 rolls 1: landed on 86. player 5 at 68 rolls 6: landed on 74. [6] rolls again! player 5 at 74 rolls 1: landed on 75. player 1 at 59 rolls 1: landed on 60. player 2 at 94 rolls 6: player wins! The winner of the game is player #2

## Raku

(formerly Perl 6)

Snakes and ladders is entirely chance based, so human interaction is not really required. This version allows up to one human player against any number of computer players and asks for input... but doesn't really *need* or even *use* it. I didn't bother to implement a graphical interface.

```
# board layout
my %snl = 4, 14, 9, 31, 17, 7, 20, 38, 28, 84, 40, 59, 51, 67, 54, 34,
62, 19, 63, 81, 64, 60, 71, 91, 87, 24, 93, 73, 95, 75, 99, 78;
my @players = 1, 1, 1; # three players, starting on square 1
my $human = 1; # player 1 is human. set to 0 for all computer players
loop {
for ^@players -> $player {
turn(@players[$player], $player + 1);
}
say '';
}
sub turn ($square is rw, $player) {
if $player == $human {
prompt "You are on square $square. Hit enter to roll the die.";
}
my $roll = (1..6).roll;
my $turn = $square + $roll;
printf "Player $player on square %2d rolls a $roll", $square;
if $turn > 100 {
say " but cannot move. Next players turn.";
return $square;
}
if %snl{$turn} {
$square = %snl{$turn};
if $turn > $square {
say ". Oops! Landed on a snake. Slither down to $square."
} else {
say ". Yay! Landed on a ladder. Climb up to $square."
}
} else {
$square = $turn;
say " and moves to square $square";
}
say "Player $player wins!" and exit if $square == 100;
return $square;
}
```

- Sample output:

You are on square 1. Hit enter to roll the die. Player 1 on square 1 rolls a 1 and moves to square 2 Player 2 on square 1 rolls a 4 and moves to square 5 Player 3 on square 1 rolls a 1 and moves to square 2 You are on square 2. Hit enter to roll the die. Player 1 on square 2 rolls a 1 and moves to square 3 Player 2 on square 5 rolls a 2 and moves to square 7 Player 3 on square 2 rolls a 3 and moves to square 5 You are on square 3. Hit enter to roll the die. Player 1 on square 3 rolls a 4 and moves to square 7 Player 2 on square 7 rolls a 1 and moves to square 8 Player 3 on square 5 rolls a 2 and moves to square 7 You are on square 7. Hit enter to roll the die. Player 1 on square 7 rolls a 2. Yay! Landed on a ladder. Climb up to 31. Player 2 on square 8 rolls a 3 and moves to square 11 Player 3 on square 7 rolls a 2. Yay! Landed on a ladder. Climb up to 31. ... about 15 turns omitted ... You are on square 90. Hit enter to roll the die. Player 1 on square 90 rolls a 3. Oops! Landed on a snake. Slither down to 73. Player 2 on square 55 rolls a 3 and moves to square 58 Player 3 on square 90 rolls a 4 and moves to square 94 You are on square 73. Hit enter to roll the die. Player 1 on square 73 rolls a 6 and moves to square 79 Player 2 on square 58 rolls a 5. Yay! Landed on a ladder. Climb up to 81. Player 3 on square 94 rolls a 3 and moves to square 97 You are on square 79. Hit enter to roll the die. Player 1 on square 79 rolls a 3 and moves to square 82 Player 2 on square 81 rolls a 6. Oops! Landed on a snake. Slither down to 24. Player 3 on square 97 rolls a 5 but cannot move. Next players turn. You are on square 82. Hit enter to roll the die. Player 1 on square 82 rolls a 5. Oops! Landed on a snake. Slither down to 24. Player 2 on square 24 rolls a 6 and moves to square 30 Player 3 on square 97 rolls a 4 but cannot move. Next players turn. You are on square 24. Hit enter to roll the die. Player 1 on square 24 rolls a 4. Yay! Landed on a ladder. Climb up to 84. Player 2 on square 30 rolls a 5 and moves to square 35 Player 3 on square 97 rolls a 4 but cannot move. Next players turn. You are on square 84. Hit enter to roll the die. Player 1 on square 84 rolls a 1 and moves to square 85 Player 2 on square 35 rolls a 2 and moves to square 37 Player 3 on square 97 rolls a 3 and moves to square 100 Player 3 wins!

## REXX

```
/*REXX program plays "Snakes and Ladders" game for any number of players (default 3). */
parse arg np seed . /*obtain optional arguments from the CL*/
if np=='' | np=="," then np= 3 /*Not specified? Then use the default.*/
if datatype(seed, 'W') then call random ,,seed /*maybe use a seed for the RANDOM BIF.*/
pad= left('',7) /*variable value used for indenting SAY*/
do k=1 for 100; @.k= k /*assign default values for board cells*/
end /*k*/ /* [↑] number when landing on a square*/
/* [↓] define ladder destinations. */
@.4=14; @.9=31; @.20=38; @.28=84; @.40=59; @.51=67; @.63=81; @.71=91; @.95=75
@.17=7; @.54=34; @.62=19; @.64=60; @.87=24; @.93=73; @.99=78
/* [↑] define snake destinations. */
player.= 1 /*start all players on the 1st square. */
do games=1 until $==100; say center(' turn ' games" ", 75, "─")
do j=1 for np until $==100; $= turn(j, player.j); player.j= $
end /*j*/ /*process each of the number of players*/
end /*games*/ /*exit both loops when there's a winner*/
say pad 'Player ' j " wins!" /*announce the winner; the game is over*/
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
turn: parse arg P, square; ?= random(1, 6) /*simulate a roll of a six─sided die. */
@does= pad 'Player ' P " on square " right(square, 2) ' rolls a ' ?
if square+?>100 then do; say @does " but can't move. Next player's turn."
return square
end
else do; square= square + ? /*move a player.*/
say @does " and moves to square" right(square, 3)
end
next= @.square /*where moved to*/
@oops= pad pad 'Oops! Landed on a snake, slither down to' right(next, 3)
@ladder= pad pad 'Yay! Landed on a ladder, climb up to' right(next, 3)
if square<next then say right(@ladder, 69)
else if square>next then say right(@oops , 69)
return next
```

- output when using the default input:

───────────────────────────────── turn 1 ───────────────────────────────── Player 1 on square 1 rolls a 5 and moves to square 6 Player 2 on square 1 rolls a 3 and moves to square 4 Yay! Landed on a ladder, climb up to 14 Player 3 on square 1 rolls a 5 and moves to square 6 ───────────────────────────────── turn 2 ───────────────────────────────── Player 1 on square 6 rolls a 5 and moves to square 11 Player 2 on square 14 rolls a 4 and moves to square 18 Player 3 on square 6 rolls a 3 and moves to square 9 Yay! Landed on a ladder, climb up to 31 ───────────────────────────────── turn 3 ───────────────────────────────── Player 1 on square 11 rolls a 6 and moves to square 17 Oops! Landed on a snake, slither down to 7 Player 2 on square 18 rolls a 3 and moves to square 21 Player 3 on square 31 rolls a 2 and moves to square 33 ───────────────────────────────── turn 4 ───────────────────────────────── Player 1 on square 7 rolls a 5 and moves to square 12 Player 2 on square 21 rolls a 4 and moves to square 25 Player 3 on square 33 rolls a 3 and moves to square 36 ───────────────────────────────── turn 5 ───────────────────────────────── Player 1 on square 12 rolls a 4 and moves to square 16 Player 2 on square 25 rolls a 3 and moves to square 28 Yay! Landed on a ladder, climb up to 84 Player 3 on square 36 rolls a 6 and moves to square 42 ───────────────────────────────── turn 6 ───────────────────────────────── Player 1 on square 16 rolls a 6 and moves to square 22 Player 2 on square 84 rolls a 1 and moves to square 85 Player 3 on square 42 rolls a 3 and moves to square 45 ───────────────────────────────── turn 7 ───────────────────────────────── Player 1 on square 22 rolls a 6 and moves to square 28 Yay! Landed on a ladder, climb up to 84 Player 2 on square 85 rolls a 3 and moves to square 88 Player 3 on square 45 rolls a 4 and moves to square 49 ───────────────────────────────── turn 8 ───────────────────────────────── Player 1 on square 84 rolls a 4 and moves to square 88 Player 2 on square 88 rolls a 6 and moves to square 94 Player 3 on square 49 rolls a 1 and moves to square 50 ───────────────────────────────── turn 9 ───────────────────────────────── Player 1 on square 88 rolls a 3 and moves to square 91 Player 2 on square 94 rolls a 4 and moves to square 98 Player 3 on square 50 rolls a 4 and moves to square 54 Oops! Landed on a snake, slither down to 34 ──────────────────────────────── turn 10 ───────────────────────────────── Player 1 on square 91 rolls a 6 and moves to square 97 Player 2 on square 98 rolls a 2 and moves to square 100 Player 2 wins!

## Ruby

```
NONE = 0; LADDER = 1; SNAKE = 2; STAY = 1; MOVE = 2; WIN = 3
class Cell
@type; @to; attr_reader :type, :to
def initialize; @type = NONE; @to = 0; end
def set( t, o ); @type = t; @to = o; end
end
class Player
@pos; @name; attr_accessor :pos; attr_reader :name
def initialize( n ); @pos = 0; @name = n; end
def play( dice )
s = dice.roll; return s, STAY if @pos + s > 99
@pos += s; return s, WIN if @pos == 99
return s, MOVE
end
end
class Die
@sides; def initialize( s = 6 ); @sides = s; end
def roll; return 1 + rand( @sides ); end
end
def initBoard
@board = Array.new( 100 ); for i in 0 .. 99; @board[i] = Cell.new(); end
@board[3].set( LADDER, 13 ); @board[8].set( LADDER, 30 ); @board[19].set( LADDER, 37 );
@board[27].set( LADDER, 83 );@board[39].set( LADDER, 58 ); @board[50].set( LADDER, 66 );
@board[62].set( LADDER, 80 ); @board[70].set( LADDER, 90 ); @board[16].set( SNAKE, 6 );
@board[61].set( SNAKE, 18 ); @board[86].set( SNAKE, 23 ); @board[53].set( SNAKE, 33 );
@board[63].set( SNAKE, 59 ); @board[92].set( SNAKE, 72 ); @board[94].set( SNAKE, 74 );
@board[98].set( SNAKE, 77 );
end
def initPlayers
@players = Array.new( 4 );
for i in 0 .. @playersCount - 1; @players[i] = Player.new( "player " << i + 49 ); end
end
def play
initBoard; initPlayers; @die = Die.new
while true
for p in 0 .. @playersCount - 1
puts; puts
if( 0 == p )
print "#{@players[p].name}, your turn. Your position is cell #{@players[p].pos + 1}.\n"<<
"Press [RETURN] to roll the die."
gets; np = @players[p].play( @die ); print "You rolled a #{np[0]}\n"
if np[1] == WIN
print "You reached position #{@players[p].pos + 1} and win the game!!!!\n"; return
elsif np[1] == STAY; print "Sorry, you cannot move!\n"
else print "Your new position is cell #{@players[p].pos + 1}.\n";
end
else
np = @players[p].play( @die ); print "#{@players[p].name} rolled a #{np[0]}.\n"
if np[1] == WIN
print "He reached position #{@players[p].pos + 1} and wins the game!!!!\n"; return
elsif np[1] == STAY; print "But he cannot move....\n"
else print "His new position is cell #{@players[p].pos + 1}.\n";
end
end
s = @board[@players[p].pos].type
next if s == NONE
@players[p].pos = @board[@players[p].pos].to
case s
when SNAKE; print "What a pitty, landed on a snake. "
when LADDER; print "Lucky move! Landed on a ladder. "
end
print "New position is cell #{@players[p].pos + 1}.\n"
end
end
end
@playersCount = 4; @board; @players; @die
play
```

- Output:

... player 1, your turn. Your position is cell 97. Press [RETURN] to roll the die. You rolled a 5 Sorry, you cannot move!

player 2 rolled a 5. His new position is cell 49.

player 3 rolled a 4. But he cannot move....

player 4 rolled a 6. His new position is cell 91.

player 1, your turn. Your position is cell 97. Press [RETURN] to roll the die. You rolled a 3 You reached position 100 and win the game!!!!

## Visual Basic .NET

```
Module Module1
ReadOnly SNL As New Dictionary(Of Integer, Integer) From {
{4, 14},
{9, 31},
{17, 7},
{20, 38},
{28, 84},
{40, 59},
{51, 67},
{54, 34},
{62, 19},
{63, 81},
{64, 60},
{71, 91},
{87, 24},
{93, 73},
{95, 75},
{99, 78}
}
ReadOnly rand As New Random
Const sixesThrowAgain = True
Function Turn(player As Integer, square As Integer) As Integer
Do
Dim roll = rand.Next(1, 6)
Console.Write("Player {0}, on square {1}, rolls a {2}", player, square, roll)
If square + roll > 100 Then
Console.WriteLine(" but cannot move.")
Else
square += roll
Console.WriteLine(" and moves to square {0}", square)
If square = 100 Then
Return 100
End If
Dim nxt = square
If SNL.ContainsKey(square) Then
nxt = SNL(nxt)
End If
If square < nxt Then
Console.WriteLine("Yay! Landed on a ladder. Climb up to {0}.", nxt)
If nxt = 100 Then
Return 100
End If
square = nxt
ElseIf square > nxt Then
Console.WriteLine("Oops! Landed on a snake. Slither down to {0}.", nxt)
square = nxt
End If
End If
If roll < 6 OrElse Not sixesThrowAgain Then
Return square
End If
Console.WriteLine("Rolled a 6 so roll again.")
Loop
End Function
Sub Main()
Dim players = {1, 1, 1}
Do
For i = 1 To players.Length
Dim ns = Turn(i, players(i - 1))
If ns = 100 Then
Console.WriteLine("Player {0} wins!", i)
Return
End If
players(i - 1) = ns
Console.WriteLine()
Next
Loop
End Sub
End Module
```

## V (Vlang)

```
import rand
const
(
snl = {4: 14, 9: 31, 17: 7, 20: 38, 28: 84, 40: 59, 51: 67, 54: 34,
62: 19, 63: 81, 64: 60, 71: 91, 87: 24, 93: 73, 95: 75, 99: 78}
)
fn main() {
// three players starting on square one
mut players := [1,1,1]
mut ns := 0
for {
for i, s in players {
ns = turn(i + 1, s)
if ns == 100 {
println("Player ${i+1} wins!")
exit(0)
}
players[i] = ns
println('')
}
}
}
fn turn(player int, square int) int {
mut square2 := square
mut roll, mut next := 0, 0
for {
roll = rand.int_in_range(1, 7) or {println('Error: invalid number') exit(1)}
print("Player $player, on square $square2, rolls a $roll")
if square2 + roll > 100 {println(" but cannot move.")}
else {
square2 += roll
println(" and moves to square ${square2}.")
if square2 == 100 {return 100}
next = snl[square2]
if next!= 0 {next = snl[square2]}
else {next = square2}
if square2 < next {
println("Yay! Landed on a ladder. Climb up to ${next}.")
if next == 100 {return 100}
square2 = next
}
if square2 > next {
println("Oops! Landed on a snake. Slither down to ${next}.")
square2 = next
}
}
if roll < 6 {return square2}
println("Rolled a 6 so roll again. \n")
}
return next
}
```

- Output:

Player 1, on square 1, rolls a 6 and moves to square 7. Rolled a 6 so roll again. Player 1, on square 7, rolls a 2 and moves to square 9. Yay! Landed on a ladder. Climb up to 31. Player 2, on square 1, rolls a 1 and moves to square 2. Player 3, on square 1, rolls a 5 and moves to square 6. Player 1, on square 31, rolls a 2 and moves to square 33. Player 2, on square 2, rolls a 1 and moves to square 3. Player 3, on square 6, rolls a 5 and moves to square 11. Player 1, on square 33, rolls a 3 and moves to square 36. Player 2, on square 3, rolls a 1 and moves to square 4. Yay! Landed on a ladder. Climb up to 14. ... Player 2, on square 84, rolls a 6 and moves to square 90. Rolled a 6 so roll again. Player 2, on square 90, rolls a 1 and moves to square 91. Player 3, on square 98, rolls a 6 but cannot move. Rolled a 6 so roll again. Player 3, on square 98, rolls a 4 but cannot move. Player 1, on square 94, rolls a 2 and moves to square 96. Player 2, on square 91, rolls a 3 and moves to square 94. Player 3, on square 98, rolls a 5 but cannot move. Player 1, on square 96, rolls a 4 and moves to square 100. Player 1 wins!

## Wren

```
import "random" for Random
var rand = Random.new()
var snl = {
4: 14, 9: 31, 17: 7, 20: 38, 28: 84, 40: 59, 51: 67, 54: 34,
62: 19, 63: 81, 64: 60, 71: 91, 87: 24, 93: 73, 95: 75, 99: 78
}
var sixThrowsAgain = true
var turn = Fn.new { |player, square|
while (true) {
var roll = 1 + rand.int(6)
System.write("Player %(player), on square %(square), rolls a %(roll)")
if (square + roll > 100) {
System.print(" but cannot move.")
} else {
square = square + roll
System.print(" and moves to square %(square).")
if (square == 100) return 100
var next = snl[square]
if (!next) next = square
if (square < next) {
System.print("Yay! Landed on a ladder. Climb up to %(next).")
if (next == 100) return 100
square = next
} else if (square > next) {
System.print("Oops! Landed on a snake. Slither down to %(next).")
square = next
}
}
if (roll < 6 || !sixThrowsAgain) return square
System.print("Rolled a 6 so roll again.")
}
}
// three players starting on square one
var players = [1, 1, 1]
while (true) {
var i = 0
for (s in players) {
var ns = turn.call(i + 1, s)
if (ns == 100) {
System.print("Player %(i+1) wins!")
return
}
players[i] = ns
System.print()
i = i + 1
}
}
```

- Output:

Sample game (abridged):

Player 1, on square 1, rolls a 6 and moves to square 7. Rolled a 6 so roll again. Player 1, on square 7, rolls a 6 and moves to square 13. Rolled a 6 so roll again. Player 1, on square 13, rolls a 5 and moves to square 18. Player 2, on square 1, rolls a 2 and moves to square 3. Player 3, on square 1, rolls a 5 and moves to square 6. Player 1, on square 18, rolls a 6 and moves to square 24. Rolled a 6 so roll again. Player 1, on square 24, rolls a 4 and moves to square 28. Yay! Landed on a ladder. Climb up to 84. Player 2, on square 3, rolls a 4 and moves to square 7. Player 3, on square 6, rolls a 2 and moves to square 8. Player 1, on square 84, rolls a 6 and moves to square 90. Rolled a 6 so roll again. Player 1, on square 90, rolls a 5 and moves to square 95. Oops! Landed on a snake. Slither down to 75. .... Player 2, on square 53, rolls a 3 and moves to square 56. Player 3, on square 92, rolls a 4 and moves to square 96. Player 1, on square 39, rolls a 1 and moves to square 40. Yay! Landed on a ladder. Climb up to 59. Player 2, on square 56, rolls a 3 and moves to square 59. Player 3, on square 96, rolls a 4 and moves to square 100. Player 3 wins!

## XPL0

```
include xpllib; \for Print
def SixThrowsAgain = true;
func NextSquare(Square);
int Square;
[case Square of
4: return 14;
9: return 31;
17: return 7;
20: return 38;
28: return 84;
40: return 59;
51: return 67;
54: return 34;
62: return 19;
63: return 81;
64: return 60;
71: return 91;
87: return 24;
93: return 73;
95: return 75;
99: return 78
other return Square;
];
func Turn(Player, Square);
int Player, Square;
int Roll, Next;
[loop [Roll:= Ran(6)+1;
Print("Player %d, on square %d, rolls a %d", Player, Square, Roll);
if Square + Roll > 100 then
Print(" but cannot move.\n")
else [Square:= Square + Roll;
Print(" and moves to square %d.\n", Square);
if Square = 100 then return 100;
Next:= NextSquare(Square);
if Square < Next then
[Print("Yay! Landed on a ladder. Climb up to %d.\n", Next);
if Next = 100 then return 100;
Square:= Next;
]
else if Square > Next then
[Print("Oops! Landed on a snake. Slither down to %d.\n", Next);
Square:= Next;
];
];
if Roll < 6 or not SixThrowsAgain then return Square;
Print("Rolled a 6 so roll again.\n");
];
];
int Players, I, NS;
[Players:= [1, 1, 1]; \three Players starting on square one
loop [for I:= 0 to 3-1 do
[NS:= Turn(I+1, Players(I));
if NS = 100 then
[Print("Player %d wins!\n", I+1);
return;
];
Players(I):= NS;
CrLf(0);
];
];
]
```

- Output:

Player 1, on square 1, rolls a 5 and moves to square 6. Player 2, on square 1, rolls a 1 and moves to square 2. Player 3, on square 1, rolls a 5 and moves to square 6. Player 1, on square 6, rolls a 5 and moves to square 11. Player 2, on square 2, rolls a 4 and moves to square 6. Player 3, on square 6, rolls a 4 and moves to square 10. Player 1, on square 11, rolls a 3 and moves to square 14. Player 2, on square 6, rolls a 2 and moves to square 8. Player 3, on square 10, rolls a 4 and moves to square 14. Player 1, on square 14, rolls a 3 and moves to square 17. Oops! Landed on a snake. Slither down to 7. Player 2, on square 8, rolls a 6 and moves to square 14. Rolled a 6 so roll again. Player 2, on square 14, rolls a 2 and moves to square 16. . . . Player 3, on square 88, rolls a 6 and moves to square 94. Rolled a 6 so roll again. Player 3, on square 94, rolls a 3 and moves to square 97. Player 1, on square 80, rolls a 1 and moves to square 81. Player 2, on square 85, rolls a 6 and moves to square 91. Rolled a 6 so roll again. Player 2, on square 91, rolls a 6 and moves to square 97. Rolled a 6 so roll again. Player 2, on square 97, rolls a 3 and moves to square 100. Player 2 wins!

## Yabasic

```
// Rosetta Code problem: http://rosettacode.org/wiki/Snake_and_Ladder
// by Galileo, 04/2022
data 4, 14, 9, 31, 17, 7, 20, 38, 28, 84, 40, 59, 51, 67, 54, 34, 62, 19, 63, 81, 64, 60, 71, 91, 87, 24, 93, 73, 95, 75, 99, 78
dim table(100), player(2)
for n = 1 to 16 : read o, d : table(o) = d : next
player(1) = 1 : player(2) = 1
turn = 1
do
steps = int(ran(6)) + 1
nextPos = player(turn) + steps
print "Player ", turn, " on square ", player(turn), " rolls a ", steps;
if not (nextPos > 100) then
print " and moves to square ", nextPos, "."
player(turn) = nextPos
if nextPos = 100 print "Player ", turn, " wins!" : break
if table(nextPos) then
player(turn) = table(nextPos)
if table(nextPos) > nextPos then
print "Yay! Landed on a ladder. Climb up to ";
else
print "Oops! Landed on a snake. Slither down to ";
end if
print player(turn), "."
end if
else
print " but cannot move."
end if
if steps = 6 then
print "Rolled a 6, so roll again."
else
turn = turn + 1 : if turn > 2 turn = 1
end if
print
loop
```

- Output:

Player 1 on square 1 rolls a 4 and moves to square 5. Player 2 on square 1 rolls a 3 and moves to square 4. Yay! Landed on a ladder. Climb up to 14. Player 1 on square 5 rolls a 4 and moves to square 9. Yay! Landed on a ladder. Climb up to 31. Player 2 on square 14 rolls a 2 and moves to square 16. Player 1 on square 31 rolls a 6 and moves to square 37. Rolled a 6, so roll again. Player 1 on square 37 rolls a 3 and moves to square 40. Yay! Landed on a ladder. Climb up to 59. Player 2 on square 16 rolls a 5 and moves to square 21. Player 1 on square 59 rolls a 1 and moves to square 60. Player 2 on square 21 rolls a 6 and moves to square 27. Rolled a 6, so roll again. Player 2 on square 27 rolls a 1 and moves to square 28. Yay! Landed on a ladder. Climb up to 84. Player 1 on square 60 rolls a 4 and moves to square 64. Oops! Landed on a snake. Slither down to 60. Player 2 on square 84 rolls a 1 and moves to square 85. Player 1 on square 60 rolls a 2 and moves to square 62. Oops! Landed on a snake. Slither down to 19. Player 2 on square 85 rolls a 4 and moves to square 89. Player 1 on square 19 rolls a 1 and moves to square 20. Yay! Landed on a ladder. Climb up to 38. Player 2 on square 89 rolls a 3 and moves to square 92. Player 1 on square 38 rolls a 6 and moves to square 44. Rolled a 6, so roll again. Player 1 on square 44 rolls a 5 and moves to square 49. Player 2 on square 92 rolls a 4 and moves to square 96. Player 1 on square 49 rolls a 2 and moves to square 51. Yay! Landed on a ladder. Climb up to 67. Player 2 on square 96 rolls a 5 but cannot move. Player 1 on square 67 rolls a 6 and moves to square 73. Rolled a 6, so roll again. Player 1 on square 73 rolls a 3 and moves to square 76. Player 2 on square 96 rolls a 6 but cannot move. Rolled a 6, so roll again. Player 2 on square 96 rolls a 4 and moves to square 100. Player 2 wins! ---Program done, press RETURN---