Snake and ladder
Snake and ladder is a 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.
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.
C
<lang 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;
}</lang>
C++
<lang cpp>#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;
}</lang>
C#
<lang csharp>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 {0}, rolls a {0}", 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();
}
}
}
}
}</lang>
D
<lang 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;
}
}
}</lang>
- 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!
Go
<lang 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()
}
}
}</lang>
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. <lang j>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</lang>
Example Usage: <lang j> 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!</lang>
Java
<lang 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();
}
}
}
}</lang>
Kotlin
This includes an option for the player to automatically roll again when a six is rolled which I believe is a common variation: <lang scala>// 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()
}
}
}</lang>
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!
Modula-2
<lang modula2>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.</lang>
Perl
<lang 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
}</lang>
- 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.
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.
<lang perl6> # 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;
}</lang>
- 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!
Phix
<lang Phix>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
sequence players = {1,1,1} -- three players starting on square one while true do
for i=1 to length(players) do
integer ns = Turn(i, players[i])
if ns==100 then
printf(1,"Player %d wins!\n",i)
return
end if
players[i] = ns
end for
end while</lang>
- 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!
Python
<lang 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()</lang>
Racket
<lang 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))))</lang>
- 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
REXX
<lang rexx>/*REXX program to play "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 from 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</lang>
- 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
<lang 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 </lang>
- 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!!!!