# Two bullet roulette

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

The following is supposedly a question given to mathematics graduates seeking jobs on Wall Street:

A revolver handgun has a revolving cylinder with six chambers for bullets.

It is loaded with the following procedure:

1. Check the first chamber to the right of the trigger for a bullet. If a bullet is seen, the cylinder is rotated one chamber clockwise and the next chamber checked until an empty chamber is found.

2. A cartridge containing a bullet is placed in the empty chamber.

3. The cylinder is then rotated one chamber clockwise.

To randomize the cylinder's position, the cylinder is spun, which causes the cylinder to take a random position from 1 to 6 chamber rotations clockwise from its starting position.

When the trigger is pulled the gun will fire if there is a bullet in position 0, which is just counterclockwise from the loading position.

The gun is unloaded by removing all cartridges from the cylinder.

According to the legend, a suicidal Russian imperial military officer plays a game of Russian roulette by putting two bullets in a six-chamber cylinder and pulls the trigger twice. If the gun fires with a trigger pull, this is considered a successful suicide.

The cylinder is always spun before the first shot, but it may or may not be spun after putting in the first bullet and may or may not be spun after taking the first shot.

Which of the following situations produces the highest probability of suicide?

A. Spinning the cylinder after loading the first bullet, and spinning again after the first shot.

C. Spinning the cylinder after firing the first shot only.

D. Not spinning the cylinder either after loading the first bullet or after the first shot.

E. The probability is the same for all cases.

1. Run a repeated simulation of each of the above scenario, calculating the percentage of suicide with a randomization of the four spinning, loading and firing order scenarios.
2. Show the results as a percentage of deaths for each type of scenario.
3. The hand calculated probabilities are 5/9, 7/12, 5/9, and 1/2. A correct program should produce results close enough to those to allow a correct response to the interview question.

Reference

Youtube video on the Russian 1895 Nagant revolver []

## 11l

Translation of: Go
```UInt32 seed = 0
F nonrandom(n)
:seed = 1664525 * :seed + 1013904223
R Int(:seed >> 16) % n

V cylinder = [0B] * 6

F rshift()
V t = :cylinder
L(i) (4..0).step(-1)
:cylinder[i + 1] = :cylinder[i]
:cylinder = t

L(i) 6
:cylinder[i] = 0B

L :cylinder
rshift()
:cylinder = 1B
rshift()

F spin()
L 1..nonrandom(6)
rshift()

F fire()
V shot = :cylinder
rshift()
R shot

F method(s)
L(c) s
S c
‘L’
‘S’
spin()
‘F’
I fire()
R 1
R 0

F mstring(s)
[String] l
L(c) s
S c
‘L’
‘S’
l [+]= ‘spin’
‘F’
l [+]= ‘fire’
R l.join(‘, ’)

V tests = 100000
L(m) [‘LSLSFSF’, ‘LSLSFF’, ‘LLSFSF’, ‘LLSFF’]
V sum = 0
L 0 .< tests
sum += method(m)
V pc = Float(sum) * 100 / tests
print(‘#<40 produces #2.3% deaths.’.format(mstring(m), pc))```
Output:
```load, spin, load, spin, fire, spin, fire produces 55.434% deaths.
```

## AutoHotkey

```methods =
(
)

for i, method in StrSplit(methods, "`n", "`r"){
death := 0
main:
loop 100000	{
sixGun := []
for i, v in StrSplit(StrReplace(method," "), ",")
if %v%()
continue, main
}
output .= Format("{1:0.3f}", death/1000) "% Deaths for : """ method """`n"
}
MsgBox % output
return

global
if !sixGun.Count()
sixGun := [0,1,0,0,0,0]
else
if sixGun
sixGun := 1
sixGun := 1
}
fire(){
global
if bullet := sixGun
death++
temp := sixGun
loop, 5
sixGun[7-A_Index] := sixGun[6-A_Index]
sixGun := temp
return bullet
}
spin(){
global
Random, rnd, 1, 12
loop, % rnd	{
temp := sixGun
loop, 5
sixGun[7-A_Index] := sixGun[6-A_Index]
sixGun := temp
}
}
```
Output:
```55.478% Deaths for : "load, spin, load, spin, fire, spin, fire"

## C

Translation of: Go
```#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

static int nextInt(int size) {
return rand() % size;
}

static bool cylinder;

static void rshift() {
bool t = cylinder;
int i;
for (i = 4; i >= 0; i--) {
cylinder[i + 1] = cylinder[i];
}
cylinder = t;
}

int i;
for (i = 0; i < 6; i++) {
cylinder[i] = false;
}
}

while (cylinder) {
rshift();
}
cylinder = true;
rshift();
}

static void spin() {
int lim = nextInt(6) + 1;
int i;
for (i = 1; i < lim; i++) {
rshift();
}
}

static bool fire() {
bool shot = cylinder;
rshift();
return shot;
}

static int method(const char *s) {
for (; *s != '\0'; s++) {
switch (*s) {
case 'L':
break;
case 'S':
spin();
break;
case 'F':
if (fire()) {
return 1;
}
break;
}
}
return 0;
}

static void append(char *out, const char *txt) {
if (*out != '\0') {
strcat(out, ", ");
}
strcat(out, txt);
}

static void mstring(const char *s, char *out) {
for (; *s != '\0'; s++) {
switch (*s) {
case 'L':
break;
case 'S':
append(out, "spin");
break;
case 'F':
append(out, "fire");
break;
}
}
}

static void test(char *src) {
char buffer = "";
const int tests = 100000;
int sum = 0;
int t;
double pc;

for (t = 0; t < tests; t++) {
sum += method(src);
}

mstring(src, buffer);
pc = 100.0 * sum / tests;

printf("%-40s produces %6.3f%% deaths.\n", buffer, pc);
}

int main() {
srand(time(0));

test("LSLSFSF");
test("LSLSFF");
test("LLSFSF");
test("LLSFF");

return 0;
}
```
Output:
```load, spin, load, spin, fire, spin, fire produces 55.456% deaths.

## C++

Translation of: C
```#include <array>
#include <iomanip>
#include <iostream>
#include <random>
#include <sstream>

class Roulette {
private:
std::array<bool, 6> cylinder;

std::mt19937 gen;
std::uniform_int_distribution<> distrib;

int next_int() {
return distrib(gen);
}

void rshift() {
std::rotate(cylinder.begin(), cylinder.begin() + 1, cylinder.end());
}

std::fill(cylinder.begin(), cylinder.end(), false);
}

while (cylinder) {
rshift();
}
cylinder = true;
rshift();
}

void spin() {
int lim = next_int();
for (int i = 1; i < lim; i++) {
rshift();
}
}

bool fire() {
auto shot = cylinder;
rshift();
return shot;
}

public:
Roulette() {
std::random_device rd;
gen = std::mt19937(rd());
distrib = std::uniform_int_distribution<>(1, 6);

}

int method(const std::string &s) {
for (auto c : s) {
switch (c) {
case 'L':
break;
case 'S':
spin();
break;
case 'F':
if (fire()) {
return 1;
}
break;
}
}
return 0;
}
};

std::string mstring(const std::string &s) {
std::stringstream ss;
bool first = true;

auto append = [&ss, &first](const std::string s) {
if (first) {
first = false;
} else {
ss << ", ";
}
ss << s;
};

for (auto c : s) {
switch (c) {
case 'L':
break;
case 'S':
append("spin");
break;
case 'F':
append("fire");
break;
}
}

return ss.str();
}

void test(const std::string &src) {
const int tests = 100000;
int sum = 0;

Roulette r;
for (int t = 0; t < tests; t++) {
sum += r.method(src);
}

double pc = 100.0 * sum / tests;

std::cout << std::left << std::setw(40) << mstring(src) << " produces " << pc << "% deaths.\n";
}

int main() {
test("LSLSFSF");
test("LSLSFF");
test("LLSFSF");
test("LLSFF");

return 0;
}
```
Output:
```load, spin, load, spin, fire, spin, fire produces 55.487% deaths.

## EasyLang

Translation of: C
```len cyl[] 6
proc rshift . .
h = cyl
for i = 6 downto 2
cyl[i] = cyl[i - 1]
.
cyl = h
.
for i = 1 to 6
cyl[i] = 0
.
.
while cyl = 1
rshift
.
cyl = 1
rshift
.
proc spin . .
lim = random 6
for i = 1 to lim - 1
rshift
.
.
func fire .
shot = cyl
rshift
return shot
.
func method m[] .
for m in m[]
if m = 1
elif m = 2
spin
elif m = 3
if fire = 1
return 1
.
.
.
return 0
.
method\$[] = [ "load" "spin" "fire" ]
proc test m[] . .
n = 100000
for i = 1 to n
sum += method m[]
.
for i = 1 to len m[]
write method\$[m[i]] & " "
.
print "-> " & 100 * sum / n & "% death"
.
test [ 1 2 1 2 3 2 3 ]
test [ 1 2 1 2 3 3 ]
test [ 1 1 2 3 2 3 ]
test [ 1 1 2 3 3 ]
```

## Factor

Translation of: Julia
Translation of: Python
```USING: accessors assocs circular formatting fry kernel literals
math random sequences ;
IN: rosetta-code.roulette

CONSTANT: cyl \$[ { f f f f f f } <circular> ]

: cylinder ( -- seq ) cyl [ drop f ] map! ;

: load ( seq -- seq' )
0 over nth [ dup rotate-circular ] when
t 0 rot [ set-nth ] [ rotate-circular ] [ ] tri ;

: spin ( seq -- seq' ) [ 6 random 1 + + ] change-start ;

: fire ( seq -- ? seq' )
[ 0 swap nth ] [ rotate-circular ] [ ] tri ;

: LSLSFSF ( -- ? ) cylinder load spin load spin fire spin fire drop or ;
: LSLSFF  ( -- ? ) cylinder load spin load spin fire fire drop or ;
: LLSFSF  ( -- ? ) cylinder load load spin fire spin fire drop or ;
: LLSFF   ( -- ? ) cylinder load load spin fire fire drop or ;

: percent ( ... n quot: ( ... -- ... ? ) -- ... x )
0 -rot '[ _ call( -- ? ) 1 0 ? + ] [ times ] keepd /f 100 * ; inline

: run-test ( description quot -- )
100,000 swap percent
"Method <%s> produces %.3f%% deaths.\n" printf ;

: main ( -- )
{
{ "load, spin, load, spin, fire, spin, fire" [ LSLSFSF ] }
} [ run-test ] assoc-each ;

MAIN: main
```
Output:
`"rosetta-code.roulette" run`
```Method <load, spin, load, spin, fire, spin, fire> produces 55.598% deaths.
```

## Go

Translation of: Wren

Though procedural rather than OO.

```package main

import (
"fmt"
"math/rand"
"strings"
"time"
)

var cylinder = bool{}

func rshift() {
t := cylinder
for i := 4; i >= 0; i-- {
cylinder[i+1] = cylinder[i]
}
cylinder = t
}

for i := 0; i < 6; i++ {
cylinder[i] = false
}
}

for cylinder {
rshift()
}
cylinder = true
rshift()
}

func spin() {
var lim = 1 + rand.Intn(6)
for i := 1; i < lim; i++ {
rshift()
}
}

func fire() bool {
shot := cylinder
rshift()
return shot
}

func method(s string) int {
for _, c := range s {
switch c {
case 'L':
case 'S':
spin()
case 'F':
if fire() {
return 1
}
}
}
return 0
}

func mstring(s string) string {
var l []string
for _, c := range s {
switch c {
case 'L':
case 'S':
l = append(l, "spin")
case 'F':
l = append(l, "fire")
}
}
return strings.Join(l, ", ")
}

func main() {
rand.Seed(time.Now().UnixNano())
tests := 100000
for _, m := range []string{"LSLSFSF", "LSLSFF", "LLSFSF", "LLSFF"} {
sum := 0
for t := 1; t <= tests; t++ {
sum += method(m)
}
pc := float64(sum) * 100 / float64(tests)
fmt.Printf("%-40s produces %6.3f%% deaths.\n", mstring(m), pc)
}
}
```
Output:

Sample run:

```load, spin, load, spin, fire, spin, fire produces 55.267% deaths.
```

## Java

```import java.util.BitSet;

public class TwoBulletRoulette {

public static void main(String[] aArgs) {
Revolver handgun = new Revolver();
final int simulationCount = 100_000;

for ( Situation situation : Situation.values() ) {
double deaths = 0.0;
for ( int i = 0; i < simulationCount; i++ ) {
ResultState resultState = handgun.operateInMode(situation);
if ( resultState == ResultState.DEAD) {
deaths += 1.0;
}
}
final double deathRate = ( deaths / simulationCount ) * 100;
String percentage = String.format("%4.1f%%", deathRate);
System.out.println("Situation " + situation + " produces " + percentage + " deaths");
}
}

}

enum Situation { A, B, C, D }

enum ResultState { ALIVE, DEAD }

/**
* Representation of a six cylinder revolving chamber pistol.
*/
class Revolver {

public Revolver() {
chambers = new BitSet(chamberCount);
}

public ResultState operateInMode(Situation aSituation) {
return switch ( aSituation ) {
case A -> useSituationA();
case B -> useSituationB();
case C -> useSituationC();
case D -> useSituationD();
};
}

// PRIVATE //

chambers.clear();
}

rotateClockwise();
}
rotateClockwise();
}

private void spin() {
final int spins = random.nextInt(0, chamberCount);
for ( int i = 0; i < spins; i++ ) {
rotateClockwise();
}
}

private boolean fire() {
boolean fire = chambers.get(firingChamber);
chambers.set(firingChamber, false);
rotateClockwise();
return fire;
}

private void rotateClockwise() {
final boolean temp = chambers.get(chamberCount - 1);
for ( int i = chamberCount - 2; i >= 0; i-- ) {
chambers.set(i + 1, chambers.get(i));
}
chambers.set(firingChamber, temp);
}

private ResultState useSituationA() {
spin();
spin();
if ( fire() ) {
};
spin();
if ( fire() ) {
};

return ResultState.ALIVE;
}

private ResultState useSituationB() {
spin();
spin();
if ( fire() ) {
};
if ( fire() ) {
};

return ResultState.ALIVE;
}

private ResultState useSituationC() {
spin();
if ( fire() ) {
};
spin();
if ( fire() ) {
};

return ResultState.ALIVE;
}

private ResultState useSituationD() {
spin();
if ( fire() ) {
};
if ( fire() ) {
};

return ResultState.ALIVE;
}

private BitSet chambers;

private final int firingChamber = 0;
private final int chamberCount = 6;

}
```
Output:
```Situation A produces 55.6% deaths
Situation B produces 58.2% deaths
Situation C produces 55.7% deaths
Situation D produces 49.7% deaths
```

## JavaScript

```let Pistol = function(method) {
this.fired = false;
this.cylinder = new Array(6).fill(false);
this.trigger = 0;
this.rshift = function() {
this.trigger = this.trigger == 0 ? 5 : this.trigger-1;
}
while (this.cylinder[this.trigger]) this.rshift();
this.cylinder[this.trigger] = true;
this.rshift();
}
// actually we don't need this here: just for completeness
this.unload = function() { this.cylinder.fill(false); }

this.spin = function() { this.trigger = Math.floor(Math.random() * 6); }
this.fire = function() {
if (this.cylinder[this.trigger]) this.fired = true;
this.rshift();
}
this.exec = function() {
if (!method) console.error('No method provided');
else {
method = method.toUpperCase();
for (let x = 0; x < method.length; x++)
switch (method[x]) {
case 'F' : this.fire(); break;
case 'S' : this.spin(); break;
default: console.error(`Unknown character in method: \${method[x]}`);
}
return this.fired;
}
}
}

// simulating
const ITERATIONS = 25e4;
let methods = 'lslsfsf lslsff llsfsf llsff'.split(' '),
bodyCount;
console.log(`@ \${ITERATIONS.toLocaleString('en')} iterations:`);
console.log();
for (let x = 0; x < methods.length; x++) {
bodyCount = 0;
for (let y = 1; y <= ITERATIONS; y++)
if (new Pistol(methods[x]).exec()) bodyCount++;
console.log(`\${methods[x]}:`);
console.log(`deaths: \${bodyCount.toLocaleString('en')} (\${(bodyCount / ITERATIONS * 100).toPrecision(3)} %) `);
console.log();
}
```
Output:

Example:

```@ 250,000 iterations:

lslsfsf:
deaths: 139,030 (55.6 %)

lslsff:
deaths: 145,912 (58.4 %)

llsfsf:
deaths: 138,628 (55.5 %)

llsff:
deaths: 125,268 (50.1 %)
```

## Julia

Translation of: Python
```const cyl = zeros(Bool, 6)

while cyl
cyl .= circshift(cyl, 1)
end
cyl = true
cyl .= circshift(cyl, 1)
end

spin() = (cyl .= circshift(cyl, rand(1:6)))

fire() = (shot = cyl; cyl .= circshift(cyl, 1); shot)

function LSLSFSF()
cyl .= 0
fire() && return true
spin(); return fire()
end

function LSLSFF()
cyl .= 0
fire() && return true
return fire()
end

function LLSFSF()
cyl .= 0
fire() && return true
spin(); return fire()
end

function LLSFF()
cyl .= 0
fire() && return true
return fire()
end

function testmethods(N = 10000000)
for (name, method) in [("load, spin, load, spin, fire, spin, fire", LSLSFSF),
percentage = 100 * sum([method() for _ in 1:N]) / N
println("Method \$name produces \$percentage per cent deaths.")
end
end

testmethods()
```
Output:
```Method load, spin, load, spin, fire, spin, fire produces 55.54253 per cent deaths.
Method load, spin, load, spin, fire, fire produces 58.32598 per cent deaths.
Method load, load, spin, fire, spin, fire produces 55.54244 per cent deaths.
```

## Kotlin

Translation of: C
```import kotlin.random.Random

val cylinder = Array(6) { false }

fun rShift() {
val t = cylinder[cylinder.size - 1]
for (i in (0 until cylinder.size - 1).reversed()) {
cylinder[i + 1] = cylinder[i]
}
cylinder = t
}

for (i in cylinder.indices) {
cylinder[i] = false
}
}

while (cylinder) {
rShift()
}
cylinder = true
rShift()
}

fun spin() {
val lim = Random.nextInt(0, 6) + 1
for (i in 1..lim) {
rShift()
}
}

fun fire(): Boolean {
val shot = cylinder
rShift()
return shot
}

fun method(s: String): Int {
for (c in s) {
when (c) {
'L' -> {
}
'S' -> {
spin()
}
'F' -> {
if (fire()) {
return 1
}
}
}
}
return 0
}

fun mString(s: String): String {
val buf = StringBuilder()
fun append(txt: String) {
if (buf.isNotEmpty()) {
buf.append(", ")
}
buf.append(txt)
}
for (c in s) {
when (c) {
'L' -> {
}
'S' -> {
append("spin")
}
'F' -> {
append("fire")
}
}
}
return buf.toString()
}

fun test(src: String) {
val tests = 100000
var sum = 0

for (t in 0..tests) {
sum += method(src)
}

val str = mString(src)
val pc = 100.0 * sum / tests
println("%-40s produces %6.3f%% deaths.".format(str, pc))
}

fun main() {
test("LSLSFSF");
test("LSLSFF");
test("LLSFSF");
test("LLSFF");
}
```
Output:
```load, spin, load, spin, fire, spin, fire produces 55.638% deaths.

## Mathematica/Wolfram Language

```ClearAll[Unload, Load, Spin, Fire]
While[s[],
s = RotateRight[s, 1]
];
s[] = True;
s
]
Spin[state_List] := RotateRight[state, RandomInteger[{1, 6}]]
Fire[state_List] := Module[{shot},
shot = First[state];
{RotateRight[state, 1], shot}
]
ClearAll[LSLSFSF]
LSLSFSF[] := Module[{state, shot},
state = Spin[state];
state = Spin[state];
{state, shot} = Fire[state];
If[shot,
Return[True]
];
state = Spin[state];
{state, shot} = Fire[state];
If[shot,
Return[True]
];
Return[False]
]
ClearAll[LSLSFF]
LSLSFF[] := Module[{state, shot},
state = Spin[state];
state = Spin[state];
{state, shot} = Fire[state];
If[shot,
Return[True]
];
{state, shot} = Fire[state];
If[shot,
Return[True]
];
Return[False]
]
ClearAll[LLSFSF]
LLSFSF[] := Module[{state, shot},
state = Spin[state];
{state, shot} = Fire[state];
If[shot,
Return[True]
];
state = Spin[state];
{state, shot} = Fire[state];
If[shot,
Return[True]
];
Return[False]
]
ClearAll[LLSFF]
LLSFF[] := Module[{state, shot},
state = Spin[state];
{state, shot} = Fire[state];
If[shot,
Return[True]
];
{state, shot} = Fire[state];
If[shot,
Return[True]
];
Return[False]
]
n = 10^5;
Count[Table[LSLSFSF[], n], True]/N[n]
Count[Table[LSLSFF[], n], True]/N[n]
Count[Table[LLSFSF[], n], True]/N[n]
Count[Table[LLSFF[], n], True]/N[n]
```
Output:
```0.55243
0.58272
0.55423
0.49975```

## Nim

```import algorithm, random, sequtils, strformat, strutils, tables

type
Revolver = array[6, bool]
Action {.pure.} = enum Load, Spin, Fire, Error

const Actions = {'L': Load, 'S': Spin, 'F': Fire}.toTable

func spin(revolver: var Revolver; count: Positive) =
revolver.rotateLeft(-count)

while revolver:
revolver.spin(1)
revolver = true
revolver.spin(1)

func fire(revolver: var Revolver): bool =
result = revolver
revolver.spin(1)

proc test(scenario: string) =
let actions = scenario.mapIt(Actions.getOrDefault(it, Error))
var deaths = 0
var count = 100_000
for _ in 1..count:
var revolver: Revolver
for action in actions:
case action
of Spin:
revolver.spin(rand(1..6))
of Fire:
if revolver.fire():
inc deaths
break
of Error:
raise newException(ValueError, "encountered an unknown action.")
echo &"""{100 * deaths / count:5.2f}% deaths for scenario {actions.join(", ")}."""

randomize()
for scenario in ["LSLSFSF", "LSLSFF", "LLSFSF", "LLSFF"]:
test(scenario)
```
Output:
```55.73% deaths for scenario Load, Spin, Load, Spin, Fire, Spin, Fire.

## Odin

```/* imports */
import "core:fmt"
import "core:strings"
import "core:math/rand"
/* globals */
cylinder := bool{}
/* main block */
main :: proc() {
rand.set_global_seed(42)
tests := 100000
sequence := [?]string{"LSLSFSF", "LSLSFF", "LLSFSF", "LLSFF"}
for m in sequence {
sum := 0
for t in 0 ..< tests {
sum += method(m)
}
pc: f64 = cast(f64)sum * 100 / cast(f64)tests
fmt.printf("%-40s produces %6.3f%% deaths.\n", mstring(m), pc)
}
}
/* definitions */
rshift :: proc() {
t := cylinder[len(cylinder) - 1]
copy(cylinder[1:], cylinder[0:])
cylinder = t
}
cylinder = false // array programming
}
for cylinder {
rshift()
}
cylinder = true
rshift()
}
spin :: proc() {
data: []int = {1, 2, 3, 4, 5, 6}
lim := rand.choice(data[:])
for i in 0 ..< lim {
rshift()
}
}
fire :: proc() -> bool {
shot := cylinder
rshift()
return shot
}
method :: proc(s: string) -> int {
for character in s {
switch character {
case 'L':
case 'S':
spin()
case 'F':
if fire() {
return 1
}
}
}
return 0
}
mstring :: proc(s: string) -> string {
l: [dynamic]string
for character in s {
switch character {
case 'L':
case 'S':
append(&l, "spin")
case 'F':
append(&l, "fire")
}
}
return strings.join(l[:], ", ")
}
```
Output:
```load, spin, load, spin, fire, spin, fire produces 55.771% deaths.
```

## Perl

Translation of: Raku
```use strict;
use warnings;
use feature 'say';

my @cyl;
my \$shots = 6;

push @cyl, shift @cyl while \$cyl;
\$cyl = 1;
push @cyl, shift @cyl
}

sub spin  { push @cyl, shift @cyl for 0 .. int rand @cyl }
sub fire  { push @cyl, shift @cyl; \$cyl }

sub LSLSFSF {
@cyl = (0) x \$shots;
return 1 if fire;
spin;
fire
}

sub LSLSFF {
@cyl = (0) x \$shots;
fire or fire
}

sub LLSFSF {
@cyl = (0) x \$shots;
return 1 if fire;
spin;
fire
}

sub LLSFF {
@cyl = (0) x \$shots;
fire or fire
}

my \$trials = 10000;

for my \$ref (<LSLSFSF LSLSFF LLSFSF LLSFF>) {
no strict 'refs';
my \$total = 0;
\$total += &\$ref for 1..\$trials;
printf "%7s %.2f%%\n", \$ref, \$total / \$trials * 100;
}
```
Output:
```LSLSFSF 55.04%
LSLSFF 58.77%
LLSFSF 55.09%
LLSFF 50.13%```

## Phix

```with javascript_semantics
function spin(sequence revolver, integer count)
while count do
revolver = revolver[\$]&revolver[1..\$-1]
count -= 1
end while
return revolver
end function

while revolver do
revolver = spin(revolver,1)
end while
revolver = true
revolver = spin(revolver,1)
return revolver
end function

if revolver then dead = true end if
revolver = spin(revolver,1)
end function

procedure test(sequence me)
{string method, atom expected} = me
integer deaths = 0,
limit = 100_000
for n=1 to limit do
sequence revolver = repeat(false,6)
for i=1 to length(method) do
integer ch = method[i]
switch ch
case 'S': revolver = spin(revolver,rand(6))
end switch
end for
end for
printf(1,"%s: %5.2f (expected %.2f%%)\n",{method,100*deaths/limit,expected*100})
end procedure

papply({{"LSLSFSF",5/9},{"LSLSFF",7/12},{"LLSFSF",5/9},{"LLSFF",1/2}},test)
```
Output:
```Load/Spin/Fire method percentage fatalities:
LSLSFSF: 55.40 (expected 55.56%)
LSLSFF: 58.33 (expected 58.33%)
LLSFSF: 55.54 (expected 55.56%)
LLSFF: 50.03 (expected 50.00%)
```

## Python

```""" Russian roulette problem """
import numpy as np

class Revolver:
""" simulates 6-shot revolving cylinger pistol """

def __init__(self):
self.cylinder = np.array([False] * 6)

""" empty all chambers of cylinder """
self.cylinder[:] = False

while self.cylinder:
self.cylinder[:] = np.roll(self.cylinder, 1)
self.cylinder = True

def spin(self):
""" spin cylinder, randomizing position of chamber to be fired """
self.cylinder[:] = np.roll(self.cylinder, np.random.randint(1, high=7))

def fire(self):
""" pull trigger of revolver, return True if fired, False if did not fire """
shot = self.cylinder
self.cylinder[:] = np.roll(self.cylinder, 1)
return shot

def LSLSFSF(self):
self.spin()
self.spin()
if self.fire():
return True
self.spin()
if self.fire():
return True
return False

def LSLSFF(self):
self.spin()
self.spin()
if self.fire():
return True
if self.fire():
return True
return False

def LLSFSF(self):
self.spin()
if self.fire():
return True
self.spin()
if self.fire():
return True
return False

def LLSFF(self):
self.spin()
if self.fire():
return True
if self.fire():
return True
return False

if __name__ == '__main__':

REV = Revolver()
TESTCOUNT = 100000
for (name, method) in [['load, spin, load, spin, fire, spin, fire', REV.LSLSFSF],

percentage = 100 * sum([method() for _ in range(TESTCOUNT)]) / TESTCOUNT
print("Method", name, "produces", percentage, "per cent deaths.")
```
Output:
```Method load, spin, load, spin, fire, spin, fire produces 55.652 per cent deaths.
Method load, spin, load, spin, fire, fire produces 58.239 per cent deaths.
Method load, load, spin, fire, spin, fire produces 55.774 per cent deaths.
```

## Raku

```unit sub MAIN (\$shots = 6);

my @cyl;

@cyl.=rotate(-1) while @cyl;
@cyl = 1;
@cyl.=rotate(-1);
}

sub spin () { @cyl.=rotate: (^@cyl).pick }

sub fire () { @cyl.=rotate; @cyl }

sub LSLSFSF {
@cyl = 0 xx \$shots;
return 1 if fire;
spin;
fire
}

sub LSLSFF {
@cyl = 0 xx \$shots;
fire() || fire
}

sub LLSFSF {
@cyl = 0 xx \$shots;
return 1 if fire;
spin;
fire
}

sub LLSFF {
@cyl = 0 xx \$shots;
fire() || fire
}

my %revolver;
my \$trials = 100000;

for ^\$trials {
%revolver<LSLSFSF> += LSLSFSF;
%revolver<LSLSFF>  += LSLSFF;
%revolver<LLSFSF>  += LLSFSF;
%revolver<LLSFF>   += LLSFF;
}

say "{.fmt('%7s')}: %{(%revolver{\$_} / \$trials × 100).fmt('%.2f')}"
for <LSLSFSF LSLSFF LLSFSF LLSFF>
```
Sample output (default; 6 shooter):
```LSLSFSF: %55.37
LSLSFF: %58.30
LLSFSF: %55.42
LLSFF: %50.29
```

Though if you go and look at the Wikipedia article for the 1895 Nagant revolver mentioned in the task reference section, you'll see it is actually a 7 shot revolver... so, run again with 7 chambers:

`raku roulette.raku 7`

Sample output (7 shooter):
```LSLSFSF: %49.29
LSLSFF: %51.14
LLSFSF: %48.74
LLSFF: %43.08```

Or, how about a Ruger GP100 10 round revolver?

`raku roulette.raku 10`

Sample output (10 shooter):
```LSLSFSF: %36.00
LSLSFF: %37.00
LLSFSF: %36.13
LLSFF: %29.77```

Doesn't change the answers, B (LSLSFF) is definitely the worst most likely choice in all cases.

## REXX

Translation of: GO

This REXX version eliminates the spinning of the bullet chamber if the random number for a spin is   6   (which would
normally just spin the bullet chamber around to its initial position,   thereby saving some busywork by the program).

Changing the cartridge chamber from an index array to a simple string made the program around   200%   faster.

```/*REXX pgm simulates scenarios for a two─bullet Russian roulette game with a 6 cyl. gun.*/
parse arg cyls tests seed .                      /*obtain optional arguments from the CL*/
if  cyls=='' |  cyls==","  then  cyls=      6    /*Not specified?  Then use the default.*/
if tests=='' | tests==","  then tests= 100000    /* "      "         "   "   "     "    */
if datatype(seed, 'W')  then call random ,,seed  /* "      "         "   "   "     "    */
cyls_ = cyls - 1;          @0= copies(0, cyls)   /*shortcut placeholder for cylinders-1 */
@abc= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'               /*indices for the various options used.*/
scenarios= 'LSLSFsF  LSLSFF  LLSFSF  LLSFF'      /*the list of scenarios to be tested.  */
#= words(scenarios)                              /*the number of actions in a scenario. */
/*The scenarios are case insensitive.  */
do m=1  for #;     q= word(scenarios, m) /*test each of the scenarios specified.*/
sum= 0                /*initialize the  sum  to zero.        */
do tests;       sum= sum + method()   /*added the sums up for the percentages*/
end   /*tests*/
pc= left( (sum * 100 / tests)"%",  7)
say act()   '  (option'     substr(@abc, m, 1)")   produces  "    pc    ' deaths.'
end   /*m*/
exit 0                                           /*stick a fork in it,  we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
fire:   != left(@, 1);      @= right(@, cyls_)left(@, 1);   /* ◄──── next cyl.*/  return !
load:   if left(@, 1)  then @= right(@, cyls_)left(@, 1);  @= 1||right(@, cyls_); return
spin:   ?= random(1, cyls);    if ?\==cyls  then @= substr(@ || @, ? + 1, cyls);  return
/*──────────────────────────────────────────────────────────────────────────────────────*/
method: @= @0;   do a=1  for length(q);          y= substr(q, a, 1)
else if y=='S'  then call spin
else if y=='F'  then if fire()  then return 1
end   /*a*/;                                                    return 0
/*──────────────────────────────────────────────────────────────────────────────────────*/
act:    \$=;      do a=1  for length(q);          y= substr(q, a, 1)
if y=='L'  then \$= \$", load"
if y=='S'  then \$= \$", spin"
if y=='F'  then \$= \$", fire"
end   /*a*/;                  return right( strip( strip(\$, , ",") ), 45)
```
output   when using the default inputs,   showing that 2nd option   B   has the highest probability for a suicide:
```     load, spin, load, spin, fire, spin, fire   (option A)   produces   55.44%   deaths.
```

## Ruby

```class Revolver
attr_accessor :strategy

def initialize(strategy = [:load, :spin, :shoot], num_chambers = 6) # default like Deer hunter
@chambers = Array.new(num_chambers) # by default 6 nils
@strategy = strategy
@notches, @shot_count, @loaded_count = 0, 0, 0
end

end

def spin
@chambers.rotate!(rand(1..@chambers.size))
end

@chambers.fill(nil)
end

def shoot
@chambers = nil
@chambers.rotate!
end

def play
strategy.each{|action| send(action)}
@shot_count += 1
@notches += 1 unless @chambers.count(:loaded) == @loaded_count # all bullets still there?
end
end

n = 100_000
puts "simulation of #{n} runs:"
strategies.each do |name, strategy|
gun = Revolver.new(strategy) # Revolver.new(strategy, 10) for a 10-shooter
n.times{gun.play}
puts "Strategy #{name}: #{gun.notches.fdiv(gun.shot_count)}"
end
```
Output:
```simulation of 100000 runs:
Strategy A: 0.55728
Strategy B: 0.58316
Strategy C: 0.5598
Strategy D: 0.49876
Strategy E: 0.44323
```

## V (Vlang)

Translation of: Kotlin
```import rand

__global cylinder = []bool{len:6}

fn main() {
test("LSLSFSF")
test("LSLSFF")
test("LLSFSF")
test("LLSFF")
}

fn test(src string) {
tests := 100000
mut sum := 0
for _ in 0..tests {
sum += method(src)
}
println('\${m_string(src)} produces \${100.0 * f32(sum) / f32(tests)}% deaths.')
}

fn rshift() {
t := cylinder
for i := 4; i >= 0; i-- {
cylinder[i+1] = cylinder[i]
}
cylinder = t
}

for i := 0; i < 6; i++ {
cylinder[i] = false
}
}

for cylinder {
rshift()
}
cylinder = true
rshift()
}

fn spin() {
mut lim := 1 + rand.intn(6) or {exit(1)}
for i := 1; i < lim; i++ {
rshift()
}
}

fn fire() bool {
shot := cylinder
rshift()
return shot
}

fn method(s string) int {
for c in s {
match c.ascii_str() {
'S' {spin()}
'F' {if fire() == true {return 1}}
else {}
}
}
return 0
}

fn m_string(s string) string {
mut l := []string{}
for c in s {
match c.ascii_str() {
'S' {l << "spin"}
'F' {l << "fire"}
else {}
}
}
return l.join(', ')
}```
Output:
```load, spin, load, spin, fire, spin, fire produces 55.795% deaths.
```

## Wren

Library: Wren-fmt
```import "random" for Random
import "/fmt" for Fmt

var Rand = Random.new()

class Revolver {
construct new() {
_cylinder = List.filled(6, false)
}

rshift() {
var t = _cylinder[-1]
for (i in 4..0) _cylinder[i+1] = _cylinder[i]
_cylinder = t
}

for (i in 0..5) _cylinder[i] = false
}

while (_cylinder) rshift()
_cylinder = true
rshift()
}

spin() {
for (i in 1..Rand.int(1, 7)) rshift()
}

fire() {
var shot = _cylinder
rshift()
return shot
}

method(s) {
for (c in s) {
if (c == "L") {
} else if (c == "S") {
spin()
} else if (c == "F") {
if (fire()) return 1
}
}
return 0
}

static mstring(s) {
var l = []
for (c in s) {
if (c == "L") {
} else if (c == "S") {
} else if (c == "F") {
}
}
return l.join(", ")
}
}

var rev = Revolver.new()
var tests = 100000
for (m in ["LSLSFSF", "LSLSFF", "LLSFSF", "LLSFF"]) {
var sum = 0
for (t in 1..tests) sum = sum + rev.method(m)
Fmt.print("\$-40s produces \$6.3f\% deaths.", Revolver.mstring(m), sum * 100 / tests)
}```
Output:

Sample run:

```load, spin, load, spin, fire, spin, fire produces 55.500% deaths.