Snake: Difference between revisions

From Rosetta Code
Content added Content deleted
(Added ZX Spectrum Basic)
(Added Kotlin)
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}
}
</lang>
</lang>

=={{header|Kotlin}}==
{{trans|C++}}
{{works with|Windows 10}}
<lang scala>// Kotlin Native v0.5

import kotlinx.cinterop.*
import platform.posix.*
import platform.windows.*

const val WID = 60
const val HEI = 30
const val MAX_LEN = 600
const val NUL = '\u0000'

enum class Dir { NORTH, EAST, SOUTH, WEST }

class Snake {
val console: HANDLE
var alive = false
val brd = CharArray(WID * HEI)
var dir = Dir.NORTH
val snk = nativeHeap.allocArray<COORD>(MAX_LEN)
lateinit var head: COORD
var tailIdx = 0
var headIdx = 0
var points = 0

init {
console = GetStdHandle(STD_OUTPUT_HANDLE)!!
SetConsoleTitleW("Snake")
memScoped {
val coord = alloc<COORD>().apply { X = (WID + 1).toShort(); Y = (HEI + 2).toShort() }
SetConsoleScreenBufferSize(console, coord.readValue())
val rc = alloc<SMALL_RECT>().apply {
Left = 0; Top = 0; Right = WID.toShort(); Bottom = (HEI + 1).toShort()
}
SetConsoleWindowInfo(console, TRUE, rc.ptr)
val ci = alloc<CONSOLE_CURSOR_INFO>().apply { dwSize = 1; bVisible = FALSE }
SetConsoleCursorInfo(console, ci.ptr)
}
}

fun play() {
while (true) {
createfield()
alive = true
while (alive) {
drawfield()
readKey()
moveSnake()
Sleep(50)
}
memScoped {
val c = alloc<COORD>().apply { X = 0; Y = (HEI + 1).toShort() }
SetConsoleCursorPosition(console, c.readValue())
}
SetConsoleTextAttribute(console, 0x000b)
print("Play again [Y/N]? ")
val a = readLine()!!.toLowerCase()
if (a.length > 0 && a[0] != 'y') {
nativeHeap.free(snk)
return
}
}
}

private fun createfield() {
memScoped {
val coord = alloc<COORD>().apply { X = 0; Y = 0 }
val c = alloc<DWORDVar>()
FillConsoleOutputCharacterW(console, 32, (HEI + 2) * 80, coord.readValue(), c.ptr)
FillConsoleOutputAttribute(console, 0x0000, (HEI + 2) * 80, coord.readValue(), c.ptr)
SetConsoleCursorPosition(console, coord.readValue())
}
for (x in 0 until WID * HEI) brd[x] = NUL
for (x in 0 until WID) {
brd[x + WID * (HEI - 1)] = '+'
brd[x] = '+'
}
for (y in 1 until HEI) {
brd[WID - 1 + WID * y] = '+'
brd[WID * y] = '+'
}
var xx: Int
var yy: Int
do {
xx = rand() % WID
yy = rand() % (HEI shr 1) + (HEI shr 1)
}
while (brd[xx + WID * yy] != NUL)
brd[xx + WID * yy] = '@'
tailIdx = 0
headIdx = 4
xx = 3
yy = 2
for (cc in tailIdx until headIdx) {
brd[xx + WID * yy] = '#'
snk[cc].X = (3 + cc).toShort()
snk[cc].Y = 2
}
head = snk[3]
dir = Dir.EAST
points = 0
}

private fun readKey() {
if ((GetAsyncKeyState(39).toInt() and 0x8000) != 0) dir = Dir.EAST
if ((GetAsyncKeyState(37).toInt() and 0x8000) != 0) dir = Dir.WEST
if ((GetAsyncKeyState(38).toInt() and 0x8000) != 0) dir = Dir.NORTH
if ((GetAsyncKeyState(40).toInt() and 0x8000) != 0) dir = Dir.SOUTH
}

private fun drawfield() {
memScoped {
val coord = alloc<COORD>()
var t = NUL
for (y in 0 until HEI) {
coord.Y = y.toShort()
for (x in 0 until WID) {
t = brd[x + WID * y]
if (t == NUL) continue
coord.X = x.toShort()
SetConsoleCursorPosition(console, coord.readValue())
if (coord.X == head.X && coord.Y == head.Y) {
SetConsoleTextAttribute(console, 0x002e)
print('O')
SetConsoleTextAttribute(console, 0x0000)
continue
}
when (t) {
'#' -> SetConsoleTextAttribute(console, 0x002a)
'+' -> SetConsoleTextAttribute(console, 0x0019)
'@' -> SetConsoleTextAttribute(console, 0x004c)
}
print(t)
SetConsoleTextAttribute(console, 0x0000)
}
}
print(t)
SetConsoleTextAttribute(console, 0x0007)
val c = alloc<COORD>().apply { X = 0; Y = HEI.toShort() }
SetConsoleCursorPosition(console, c.readValue())
print("Points: $points")
}
}

private fun moveSnake() {
when (dir) {
Dir.NORTH -> head.Y--
Dir.EAST -> head.X++
Dir.SOUTH -> head.Y++
Dir.WEST -> head.X--
}
val t = brd[head.X + WID * head.Y]
if (t != NUL && t != '@') {
alive = false
return
}
brd[head.X + WID * head.Y] = '#'
snk[headIdx].X = head.X
snk[headIdx].Y = head.Y
if (++headIdx >= MAX_LEN) headIdx = 0
if (t == '@') {
points++
var x: Int
var y: Int
do {
x = rand() % WID
y = rand() % (HEI shr 1) + (HEI shr 1)
}
while (brd[x + WID * y] != NUL)
brd[x + WID * y] = '@'
return
}
SetConsoleCursorPosition(console, snk[tailIdx].readValue())
print(' ')
brd[snk[tailIdx].X + WID * snk[tailIdx].Y] = NUL
if (++tailIdx >= MAX_LEN) tailIdx = 0
}
}

fun main(args: Array<String>) {
srand(time(null).toInt())
Snake().play()
}</lang>

{{output}}
<pre>
Similar to C++ entry
</pre>


=={{header|Java}}==
=={{header|Java}}==

Revision as of 16:17, 25 January 2018

Snake 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.
This page uses content from Wikipedia. The original article was at Snake_(video_game). The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)

Snake is a game where the player maneuvers a line which grows in length every time the snake reaches a food source.

Task

Implement a variant of the Snake game, in any interactive environment, in which a sole player attempts to eat items by running into them with the head of the snake. Each item eaten makes the snake longer and a new item is randomly generated somewhere else on the plane. The game ends when the snake attempts to eat himself.

BASIC

ZX Spectrum Basic

By ancient tradition, the controls are Q for up, A for down, O for left, and P for right.

A screenshot is here.

Note that lines 10 to 210 and 580 to 890—more than half the program—define graphics characters for the snake's head (facing in different directions) and for its food. If you're happy to make do with characters from the standard character set, you can easily adapt lines 220 to 570 to work on their own. The things the snake eats are supposed to be apples, although they don't look too much like them. <lang zxbasic> 10 FOR i=0 TO 7 

20 READ bits
30 POKE USR "L"+i,bits
40 NEXT i
50 FOR i=0 TO 7
60 READ bits
70 POKE USR "R"+i,bits
80 NEXT i
90 FOR i=0 TO 7

100 READ bits 110 POKE USR "P"+i,bits 120 NEXT i 130 RESTORE 740 140 FOR i=7 TO 0 STEP -1 150 READ bits 160 POKE USR "D"+i,bits 170 NEXT i 180 FOR i=0 TO 7 190 READ bits 200 POKE USR "F"+i, bits 210 NEXT i 220 PAPER 0 230 CLS 240 LET snakex=19 250 LET snakey=15 260 LET dx=-1 270 LET dy=0 280 LET s$=CHR$ 15+CHR$ 20+CHR$ 15+CHR$ 21 290 LET foodx=INT (RND*32) 300 LET foody=INT (RND*22) 310 IF SCREEN$ (foody,foodx)<>" " THEN GO TO 290 320 INK 2 330 PRINT AT foody,foodx;CHR$ 149 340 INK 4 350 INVERSE 1 360 PRINT AT CODE s$,CODE s$(1);"#" 370 INVERSE 0 380 IF INKEY$="q" AND dy=0 THEN LET dx=0: LET dy=-1 390 IF INKEY$="a" AND dy=0 THEN LET dx=0: LET dy=1 400 IF INKEY$="o" AND dx=0 THEN LET dx=-1: LET dy=0 410 IF INKEY$="p" AND dx=0 THEN LET dx=1: LET dy=0 420 IF dx=-1 THEN PRINT AT snakey,snakex;CHR$ 155 430 IF dx=1 THEN PRINT AT snakey,snakex;CHR$ 161 440 IF dy=1 THEN PRINT AT snakey,snakex;CHR$ 159 450 IF dy=-1 THEN PRINT AT snakey,snakex;CHR$ 147 460 LET s$=CHR$ snakey+CHR$ snakex+s$ 470 IF snakex=foodx AND snakey=foody THEN GO TO 290 480 PRINT AT CODE s$(LEN s$-1),CODE s$(LEN s$);" " 490 LET s$=s$( TO LEN s$-2) 500 LET snakex=snakex+dx 510 LET snakey=snakey+dy 520 IF snakex=-1 THEN LET snakex=31 530 IF snakex=32 THEN LET snakex=0 540 IF snakey=-1 THEN LET snakey=21 550 IF snakey=22 THEN LET snakey=0 560 IF SCREEN$ (snakey,snakex)="#" THEN STOP 570 GO TO 340 580 DATA BIN 00001111 590 DATA BIN 00111111 600 DATA BIN 01110011 610 DATA BIN 11110011 620 DATA BIN 11111111 630 DATA BIN 01111111 640 DATA BIN 00000111 650 DATA BIN 00011111 660 DATA BIN 11110000 670 DATA BIN 11111100 680 DATA BIN 11001110 690 DATA BIN 11001111 700 DATA BIN 11111111 710 DATA BIN 11111110 720 DATA BIN 11100000 730 DATA BIN 11111000 740 DATA BIN 00011000 750 DATA BIN 00111100 760 DATA BIN 01111100 770 DATA BIN 01111101 780 DATA BIN 11001101 790 DATA BIN 11001111 800 DATA BIN 11111111 810 DATA BIN 11111111 820 DATA BIN 00000100 830 DATA BIN 00001000 840 DATA BIN 01101011 850 DATA BIN 11111100 860 DATA BIN 11111100 870 DATA BIN 11111100 880 DATA BIN 01111111 890 DATA BIN 00110110</lang>

C++

Simple Windows console implementation.

<lang cpp>

  1. include <windows.h>
  2. include <ctime>
  3. include <iostream>
  4. include <string>

const int WID = 60, HEI = 30, MAX_LEN = 600; enum DIR { NORTH, EAST, SOUTH, WEST };

class snake { public: 

   snake() {
       console = GetStdHandle( STD_OUTPUT_HANDLE ); SetConsoleTitle( "Snake" ); 
       COORD coord = { WID + 1, HEI + 2 }; SetConsoleScreenBufferSize( console, coord );
       SMALL_RECT rc = { 0, 0, WID, HEI + 1 }; SetConsoleWindowInfo( console, TRUE, &rc );
       CONSOLE_CURSOR_INFO ci = { 1, false }; SetConsoleCursorInfo( console, &ci );
   }
   void play() {
       std::string a;
       while( 1 ) {
           createField(); alive = true;
           while( alive ) { drawField(); readKey(); moveSnake(); Sleep( 50 ); }
           COORD c = { 0, HEI + 1 }; SetConsoleCursorPosition( console, c );
           SetConsoleTextAttribute( console, 0x000b );
           std::cout << "Play again [Y/N]? "; std::cin >> a;
           if( a.at( 0 ) != 'Y' && a.at( 0 ) != 'y' ) return;
       }
   }

private: 

   void createField() {
       COORD coord = { 0, 0 }; DWORD c;
       FillConsoleOutputCharacter( console, ' ', ( HEI + 2 ) * 80, coord, &c );
       FillConsoleOutputAttribute( console, 0x0000, ( HEI + 2 ) * 80, coord, &c );
       SetConsoleCursorPosition( console, coord );
       int x = 0, y = 1; for( ; x < WID * HEI; x++ ) brd[x] = 0;
       for( x = 0; x < WID; x++ ) {
           brd[x] = brd[x + WID * ( HEI - 1 )] = '+';
       }
       for( ; y < HEI; y++ ) {
           brd[0 + WID * y] = brd[WID - 1 + WID * y] = '+';
       }
       do {
           x = rand() % WID; y = rand() % ( HEI >> 1 ) + ( HEI >> 1 );
       } while( brd[x + WID * y] );
       brd[x + WID * y] = '@';
       tailIdx = 0; headIdx = 4; x = 3; y = 2;
       for( int c = tailIdx; c < headIdx; c++ ) {
           brd[x + WID * y] = '#';
           snk[c].X = 3 + c; snk[c].Y = 2;
       }
       head = snk[3]; dir = EAST; points = 0;
   }
   void readKey() {
       if( GetAsyncKeyState( 39 ) & 0x8000 ) dir = EAST;
       if( GetAsyncKeyState( 37 ) & 0x8000 ) dir = WEST;
       if( GetAsyncKeyState( 38 ) & 0x8000 ) dir = NORTH;
       if( GetAsyncKeyState( 40 ) & 0x8000 ) dir = SOUTH;
   }
   void drawField() {
       COORD coord; char t;
       for( int y = 0; y < HEI; y++ ) {
           coord.Y = y;
           for( int x = 0; x < WID; x++ ) {
               t = brd[x + WID * y]; if( !t ) continue;
               coord.X = x; SetConsoleCursorPosition( console, coord );
               if( coord.X == head.X && coord.Y == head.Y ) {
                   SetConsoleTextAttribute( console, 0x002e );
                   std::cout << 'O'; SetConsoleTextAttribute( console, 0x0000 );
                   continue;
               }
               switch( t ) {
                   case '#': SetConsoleTextAttribute( console, 0x002a ); break;
                   case '+': SetConsoleTextAttribute( console, 0x0019 ); break;
                   case '@': SetConsoleTextAttribute( console, 0x004c ); break;
               }
               std::cout << t; SetConsoleTextAttribute( console, 0x0000 );
           }
       }
       std::cout << t; SetConsoleTextAttribute( console, 0x0007 );
       COORD c = { 0, HEI }; SetConsoleCursorPosition( console, c );
       std::cout << "Points: " << points;
   }
   void moveSnake() {
       switch( dir ) {
           case NORTH: head.Y--; break;
           case EAST: head.X++; break;
           case SOUTH: head.Y++; break;
           case WEST: head.X--; break;
       }
       char t = brd[head.X + WID * head.Y];
       if( t && t != '@' ) { alive = false; return; }
       brd[head.X + WID * head.Y] = '#';
       snk[headIdx].X = head.X; snk[headIdx].Y = head.Y;
       if( ++headIdx >= MAX_LEN ) headIdx = 0;
       if( t == '@' ) {
           points++; int x, y;
           do {
               x = rand() % WID; y = rand() % ( HEI >> 1 ) + ( HEI >> 1 );
           } while( brd[x + WID * y] );
           brd[x + WID * y] = '@'; return;
       }
       SetConsoleCursorPosition( console, snk[tailIdx] ); std::cout << ' ';
       brd[snk[tailIdx].X + WID * snk[tailIdx].Y] = 0;
       if( ++tailIdx >= MAX_LEN ) tailIdx = 0;
   }
   bool alive; char brd[WID * HEI]; 
   HANDLE console; DIR dir; COORD snk[MAX_LEN];
   COORD head; int tailIdx, headIdx, points;

}; int main( int argc, char* argv[] ) { 

   srand( static_cast<unsigned>( time( NULL ) ) );
   snake s; s.play(); return 0;

} </lang>

Kotlin

Translation of: C++
Works with: Windows 10

<lang scala>// Kotlin Native v0.5

import kotlinx.cinterop.* import platform.posix.* import platform.windows.*

const val WID = 60 const val HEI = 30 const val MAX_LEN = 600 const val NUL = '\u0000'

enum class Dir { NORTH, EAST, SOUTH, WEST }

class Snake { 

   val console: HANDLE
   var alive = false
   val brd = CharArray(WID * HEI)
   var dir = Dir.NORTH
   val snk = nativeHeap.allocArray<COORD>(MAX_LEN)
   lateinit var head: COORD
   var tailIdx = 0
   var headIdx = 0
   var points = 0

   init {
       console = GetStdHandle(STD_OUTPUT_HANDLE)!!
       SetConsoleTitleW("Snake")
       memScoped {
           val coord = alloc<COORD>().apply { X = (WID + 1).toShort(); Y = (HEI + 2).toShort() }
           SetConsoleScreenBufferSize(console, coord.readValue())
           val rc = alloc<SMALL_RECT>().apply {
               Left = 0; Top = 0; Right = WID.toShort(); Bottom = (HEI + 1).toShort()
           }
           SetConsoleWindowInfo(console, TRUE, rc.ptr)
           val ci = alloc<CONSOLE_CURSOR_INFO>().apply { dwSize = 1; bVisible = FALSE }
           SetConsoleCursorInfo(console, ci.ptr)
       }
   }

   fun play() {
       while (true) {
           createfield()
           alive = true
           while (alive) {
               drawfield()
               readKey()
               moveSnake()
               Sleep(50)
           }
           memScoped {
               val c = alloc<COORD>().apply { X = 0; Y = (HEI + 1).toShort() }
               SetConsoleCursorPosition(console, c.readValue())
           }
           SetConsoleTextAttribute(console, 0x000b)
           print("Play again [Y/N]? ")
           val a = readLine()!!.toLowerCase()
           if (a.length > 0 && a[0] != 'y') {
               nativeHeap.free(snk)
               return
           }
       }
   }

   private fun createfield() {
       memScoped {
           val coord = alloc<COORD>().apply { X = 0; Y = 0 }
           val c = alloc<DWORDVar>()
           FillConsoleOutputCharacterW(console, 32, (HEI + 2) * 80, coord.readValue(), c.ptr)
           FillConsoleOutputAttribute(console, 0x0000, (HEI + 2) * 80, coord.readValue(), c.ptr)
           SetConsoleCursorPosition(console, coord.readValue())
       }
       for (x in 0 until WID * HEI) brd[x] = NUL
       for (x in 0 until WID) {
           brd[x + WID * (HEI - 1)] = '+'
           brd[x] = '+'
       }
       for (y in 1 until HEI) {
           brd[WID - 1 + WID * y] = '+' 
           brd[WID * y] = '+'
       }
       var xx: Int
       var yy: Int
       do {
           xx = rand() % WID
           yy = rand() % (HEI shr 1) + (HEI shr 1)
       }
       while (brd[xx + WID * yy] != NUL)
       brd[xx + WID * yy] = '@'
       tailIdx = 0
       headIdx = 4
       xx = 3
       yy = 2
       for (cc in tailIdx until headIdx) {
           brd[xx + WID * yy] = '#'
           snk[cc].X = (3 + cc).toShort()
           snk[cc].Y = 2
       }
       head = snk[3]
       dir = Dir.EAST
       points = 0
   }

   private fun readKey() {
       if ((GetAsyncKeyState(39).toInt() and 0x8000) != 0) dir = Dir.EAST
       if ((GetAsyncKeyState(37).toInt() and 0x8000) != 0) dir = Dir.WEST
       if ((GetAsyncKeyState(38).toInt() and 0x8000) != 0) dir = Dir.NORTH
       if ((GetAsyncKeyState(40).toInt() and 0x8000) != 0) dir = Dir.SOUTH
   }

   private fun drawfield() {
       memScoped {
           val coord = alloc<COORD>()
           var t = NUL
           for (y in 0 until HEI) {
               coord.Y = y.toShort()
               for (x in 0 until WID) {
                   t = brd[x + WID * y]
                   if (t == NUL) continue
                   coord.X = x.toShort()
                   SetConsoleCursorPosition(console, coord.readValue())
                   if (coord.X == head.X && coord.Y == head.Y) {
                       SetConsoleTextAttribute(console, 0x002e)
                       print('O')
                       SetConsoleTextAttribute(console, 0x0000)
                       continue
                   }
                   when (t) {
                       '#' ->  SetConsoleTextAttribute(console, 0x002a)
                       '+' ->  SetConsoleTextAttribute(console, 0x0019)
                       '@' ->  SetConsoleTextAttribute(console, 0x004c)
                   }
                   print(t)
                   SetConsoleTextAttribute(console, 0x0000)
               }
           }
           print(t)
           SetConsoleTextAttribute(console, 0x0007)
           val c = alloc<COORD>().apply { X = 0; Y = HEI.toShort() }
           SetConsoleCursorPosition(console, c.readValue())
           print("Points: $points")
       }
   }

   private fun moveSnake() {
       when (dir) {
           Dir.NORTH -> head.Y--
           Dir.EAST  -> head.X++
           Dir.SOUTH -> head.Y++
           Dir.WEST  -> head.X--
       }
       val t = brd[head.X + WID * head.Y]
       if (t != NUL && t != '@') {
           alive = false
           return
       }
       brd[head.X + WID * head.Y] = '#'
       snk[headIdx].X = head.X
       snk[headIdx].Y = head.Y
       if (++headIdx >= MAX_LEN) headIdx = 0
       if (t == '@') {
           points++
           var x: Int
           var y: Int
           do {
               x = rand() % WID
               y = rand() % (HEI shr 1) + (HEI shr 1)
           }
           while (brd[x + WID * y] != NUL)
           brd[x + WID * y] = '@'
           return
       }
       SetConsoleCursorPosition(console, snk[tailIdx].readValue())
       print(' ')
       brd[snk[tailIdx].X + WID * snk[tailIdx].Y] = NUL
       if (++tailIdx >= MAX_LEN) tailIdx = 0
   }

}

fun main(args: Array<String>) { 

   srand(time(null).toInt())
   Snake().play()

}</lang>

Output:
Similar to C++ entry

Java

See Snake/Java.

JavaScript

You need the P5 Library to run this code!
Go here to play. <lang javascript> const L = 1, R = 2, D = 4, U = 8; var block = 24, wid = 30, hei = 20, frameR = 7, fruit, snake; function Snake() { 

   this.length = 1;
   this.alive = true;
   this.pos = createVector( 1, 1 );
   this.posArray = [];
   this.posArray.push( createVector( 1, 1 ) );
   this.dir = R;
   this.draw = function() {
       fill( 130, 190, 0 );
       var pos, i = this.posArray.length - 1, l = this.length;
       while( true ){
           pos = this.posArray[i--];
           rect( pos.x * block, pos.y * block, block, block );
           if( --l == 0 ) break;
       }
   }
   this.eat = function( frut ) {
       var b = this.pos.x == frut.x && this.pos.y == frut.y;
       if( b ) this.length++;
       return b;
   }
   this.overlap = function() {
       var len = this.posArray.length - 1;
       for( var i = len; i > len - this.length; i-- ) {
           tp = this.posArray[i];
           if( tp.x === this.pos.x && tp.y === this.pos.y ) return true;
       }
       return false;
   }
   this.update = function() {
       if( !this.alive ) return;
       switch( this.dir ) {
           case L:
               this.pos.x--; if( this.pos.x < 1 ) this.pos.x = wid - 2;
           break;
           case R:
               this.pos.x++; if( this.pos.x > wid - 2 ) this.pos.x = 1;
           break;
           case U:
               this.pos.y--; if( this.pos.y < 1 ) this.pos.y = hei - 2;
           break;
           case D:
               this.pos.y++; if( this.pos.y > hei - 2 ) this.pos.y = 1;
           break;
       }
       if( this.overlap() ) { this.alive = false; } else {
           this.posArray.push( createVector( this.pos.x, this.pos.y ) );
           if( this.posArray.length > 5000 ) { this.posArray.splice( 0, 1 ); }
       }
   }

} function Fruit() { 

   this.fruitTime = true;
   this.pos = createVector();
   this.draw = function() {
       fill( 200, 50, 20 );
       rect( this.pos.x * block, this.pos.y * block, block, block );
   }

   this.setFruit = function() {
       this.pos.x = floor( random( 1, wid - 1 ) );
       this.pos.y = floor( random( 1, hei - 1 ) );
       this.fruitTime = false;
   }

} function setup() { 

   createCanvas( block * wid, block * hei );
   noStroke(); frameRate( frameR );
   snake = new Snake();fruit = new Fruit();

} function keyPressed() { 

   switch( keyCode ) {
       case LEFT_ARROW: snake.dir = L; break;
       case RIGHT_ARROW: snake.dir = R; break;
       case UP_ARROW: snake.dir = U; break;
       case DOWN_ARROW: snake.dir = D;
   }

} function draw() { 

   background( color( 0, 0x22, 0 ) );
   fill( 20, 50, 120 );
   for( var i = 0; i < wid; i++ ) {
       rect( i * block, 0, block, block );
       rect( i * block, height - block, block, block );
   }
   for( var i = 1; i < hei - 1; i++ ) {
       rect( 1, i * block, block, block );
       rect( width - block, i * block, block, block );
   }
   if( fruit.fruitTime ) {
       fruit.setFruit();
       frameR += .2;
       frameRate( frameR );
   }
   fruit.draw();
   snake.update();
   if( snake.eat( fruit.pos ) ) {
       fruit.fruitTime = true;
   }
   snake.draw();
   fill( 200 );
   textStyle( BOLD ); textAlign( RIGHT ); textSize( 120 );
   text( ""+( snake.length - 1 ), 690, 440 );
   if( !snake.alive ) text( "THE END", 630, 250 );

} </lang>

Haskell

<lang haskell>{-# LANGUAGE TemplateHaskell #-} import Control.Monad.Random (getRandomRs) import Graphics.Gloss.Interface.Pure.Game import Lens.Micro ((%~), (^.), (&), set) import Lens.Micro.TH (makeLenses)

-- all data types

data Snake = Snake { _body :: [Point], _direction :: Point } makeLenses Snake

data World = World { _snake :: Snake , _food :: [Point] 

                  , _score :: Int , _maxScore :: Int }

makeLenses World

-- everything snake can do

moves (Snake b d) = Snake (step b d : init b) d eats (Snake b d) = Snake (step b d : b) d bites (Snake b _) = any (== head b) step ((x,y):_) (a,b) = (x+a, y+b)

turn (x',y') (Snake b (x,y)) | (x+x',y+y') == (0,0) = Snake b (x,y) 

                            | otherwise             = Snake b (x',y')

-- all randomness

createWorld = do xs <- map fromIntegral <$> getRandomRs (2, 38 :: Int) 

                ys <- map fromIntegral <$> getRandomRs (2, 38 :: Int)
                return (Ok, World snake (zip xs ys) 0 0)
                where
                  snake = Snake [(20, 20)] (1,0)

-- A tyny DSL for declarative description of business logic

data Status = Ok | Fail | Stop

continue = \x -> (Ok, x) stop = \x -> (Stop, x) f >>> g = \x -> case f x of { (Ok, y) -> g y; b -> b } -- chain composition f <|> g = \x -> case f x of { (Fail, _) -> g x; b -> b } -- alternative p ==> f = \x -> if p x then f x else (Fail, x) -- condition l .& f = continue . (l %~ f) -- modification l .= y = continue . set l y -- setting

-- all business logic

updateWorld _ = id >>> (snakeEats <|> snakeMoves) 

 where
   snakeEats  = (snakeFindsFood ==> (snake .& eats)) >>>
                (score .& (+1)) >>> (food .& tail)

   snakeMoves = (snakeBitesTail ==> stop) <|>
                (snakeHitsWall ==> stop) <|>
                (snake .& moves)

   snakeFindsFood w = (w^.snake & moves) `bites` (w^.food & take 1)
   snakeBitesTail w = (w^.snake) `bites` (w^.snake.body & tail)
   snakeHitsWall w  = (w^.snake.body) & head & isOutside
   isOutside (x,y) = or [x <= 0, 40 <= x, y <= 0, 40 <= y]

-- all event handing

handleEvents e (s,w) = f w 

 where f = case s of
         Ok -> case e of
           EventKey (SpecialKey k) _ _ _ -> case k of
             KeyRight -> snake .& turn (1,0)
             KeyLeft  -> snake .& turn (-1,0)
             KeyUp    -> snake .& turn (0,1)
             KeyDown  -> snake .& turn (0,-1)
             _-> continue
           _-> continue
         _-> \w -> w & ((snake.body) .= [(20,20)]) >>>
                        (maxScore .& max (w^.score)) >>> (score .= 0)

-- all graphics

renderWorld (s, w) = pictures [frame, color c drawSnake, drawFood, showScore] 

 where c = case s of { Ok -> orange; _-> red }
       drawSnake = foldMap (rectangleSolid 10 10 `at`) (w^.snake.body)
       drawFood = color blue $ circleSolid 5 `at` (w^.food & head)
       frame = color black $ rectangleWire 400 400
       showScore = color orange $ scale 0.2 0.2 $ txt `at` (-80,130)
       txt = Text $ mconcat ["Score: ", w^.score & show
                            ,"   Maximal score: ", w^.maxScore & show]
       at p (x,y) = Translate (10*x-200) (10*y-200) p

main = do world <- createWorld 

         play inW white 7 world renderWorld handleEvents updateWorld
 where inW = InWindow "The Snake" (400, 400) (10, 10)</lang>

Extra credit

It is easy to make snake to seek food automatically. Just change the first line of the updateWorld definition:

<lang haskell>updateWorld _ = id >>> snakeSeeksFood >>> (snakeEats <|> snakeMoves) </lang>

and add local definition:

<lang haskell> snakeSeeksFood w = w & snake .& turns optimalDirection 

     where
       optimalDirection = minimumBy (comparing distanceToFood) safeTurns
       
       safeTurns = filter safe [(x,y),(-y,x),(y,-x)] `ifEmpty` [(x,y)]
         where (x,y) = w^.snake.direction
               safe d = let w = w & snake %~ moves . turns d
                        in not (snakeBitesTail w || snakeHitsWall w)
               lst `ifEmpty` x = if null lst then x else lst
       
       distanceToFood d = let (a,b) = w^.snake & turns d & moves & (^.body) & head
                              (x,y) = w^.food & head
                          in (a-x)^2 + (b-y)^2</lang>

Perl

<lang perl>use utf8; use Time::HiRes qw(sleep); use Term::ANSIColor qw(colored); use Term::ReadKey qw(ReadMode ReadLine);

binmode(STDOUT, ':utf8');

use constant { 

             VOID => 0,
             HEAD => 1,
             BODY => 2,
             TAIL => 3,
             FOOD => 4,
            };

use constant { 

             LEFT  => [+0, -1],
             RIGHT => [+0, +1],
             UP    => [-1, +0],
             DOWN  => [+1, +0],
            };

use constant { 

             BG_COLOR  => "on_black",
             SLEEP_SEC => 0.05,
            };

use constant { 

             SNAKE_COLOR => ('bold green' . ' ' . BG_COLOR),
             FOOD_COLOR  => ('red'        . ' ' . BG_COLOR),
            };

use constant { 

   U_HEAD => colored('▲', SNAKE_COLOR),
   D_HEAD => colored('▼', SNAKE_COLOR),
   L_HEAD => colored('◀', SNAKE_COLOR),
   R_HEAD => colored('▶', SNAKE_COLOR),

   U_BODY => colored('╹', SNAKE_COLOR),
   D_BODY => colored('╻', SNAKE_COLOR),
   L_BODY => colored('╴', SNAKE_COLOR),
   R_BODY => colored('╶', SNAKE_COLOR),

   U_TAIL => colored('╽', SNAKE_COLOR),
   D_TAIL => colored('╿', SNAKE_COLOR),
   L_TAIL => colored('╼', SNAKE_COLOR),
   R_TAIL => colored('╾', SNAKE_COLOR),

   A_VOID => colored(' ',   BG_COLOR),
   A_FOOD => colored('❇', FOOD_COLOR),
            };

local $| = 1;

my $w = eval { `tput cols` } || 80; my $h = eval { `tput lines` } || 24; my $r = "\033[H";

my @grid = map { 

   [map { [VOID] } 1 .. $w]

} 1 .. $h;

my $dir = LEFT; my @head_pos = ($h / 2, $w / 2); my @tail_pos = ($head_pos[0], $head_pos[1] + 1);

$grid[$head_pos[0]][$head_pos[1]] = [HEAD, $dir]; # head $grid[$tail_pos[0]][$tail_pos[1]] = [TAIL, $dir]; # tail

sub create_food { 

   my ($food_x, $food_y);

   do {
       $food_x = rand($w);
       $food_y = rand($h);
   } while ($grid[$food_y][$food_x][0] != VOID);

   $grid[$food_y][$food_x][0] = FOOD;

}

create_food();

sub display { 

   my $i = 0;

   print $r, join("\n",
       map {
           join("",
               map {
                   my $t = $_->[0];
                   if ($t != FOOD and $t != VOID) {
                       my $p = $_->[1];
                       $i =
                           $p eq UP   ? 0
                         : $p eq DOWN ? 1
                         : $p eq LEFT ? 2
                         :              3;
                   }
                       $t == HEAD ? (U_HEAD, D_HEAD, L_HEAD, R_HEAD)[$i]
                     : $t == BODY ? (U_BODY, D_BODY, L_BODY, R_BODY)[$i]
                     : $t == TAIL ? (U_TAIL, D_TAIL, L_TAIL, R_TAIL)[$i]
                     : $t == FOOD ? (A_FOOD)
                     :              (A_VOID);

                 } @{$_}
               )
         } @grid
   );

}

sub move { 

   my $grew = 0;

   # Move the head
   {
       my ($y, $x) = @head_pos;

       my $new_y = ($y + $dir->[0]) % $h;
       my $new_x = ($x + $dir->[1]) % $w;

       my $cell = $grid[$new_y][$new_x];
       my $t    = $cell->[0];

       if ($t == BODY or $t == TAIL) {
           die "Game over!\n";
       }
       elsif ($t == FOOD) {
           create_food();
           $grew = 1;
       }

       # Create a new head
       $grid[$new_y][$new_x] = [HEAD, $dir];

       # Replace the current head with body
       $grid[$y][$x] = [BODY, $dir];

       # Save the position of the head
       @head_pos = ($new_y, $new_x);
   }

   # Move the tail
   if (not $grew) {
       my ($y, $x) = @tail_pos;

       my $pos   = $grid[$y][$x][1];
       my $new_y = ($y + $pos->[0]) % $h;
       my $new_x = ($x + $pos->[1]) % $w;

       $grid[$y][$x][0]         = VOID;    # erase the current tail
       $grid[$new_y][$new_x][0] = TAIL;    # create a new tail

       # Save the position of the tail
       @tail_pos = ($new_y, $new_x);
   }

}

ReadMode(3); while (1) { 

   my $key;
   until (defined($key = ReadLine(-1))) {
       move();
       display();
       sleep(SLEEP_SEC);
   }

   if    ($key eq "\e[A" and $dir ne DOWN ) { $dir = UP    }
   elsif ($key eq "\e[B" and $dir ne UP   ) { $dir = DOWN  }
   elsif ($key eq "\e[C" and $dir ne LEFT ) { $dir = RIGHT }
   elsif ($key eq "\e[D" and $dir ne RIGHT) { $dir = LEFT  }

}</lang>

Perl 6

Works with: Rakudo version 2016.08

This is a variation of a demo script included in the examples folder for the Perl 6 SDL2::Raw library bindings.

<lang perl6>use SDL2::Raw; use Cairo;

constant W = 1280; constant H = 960;

constant FIELDW = W div 32; constant FIELDH = H div 32;

SDL_Init(VIDEO);

my $window = SDL_CreateWindow( 

   'Snake',
   SDL_WINDOWPOS_CENTERED_MASK,
   SDL_WINDOWPOS_CENTERED_MASK,
   W, H,
   OPENGL

);

my $render = SDL_CreateRenderer($window, -1, ACCELERATED +| PRESENTVSYNC);

my $snake_image = Cairo::Image.record( 

   -> $_ {
       .save;
       .rectangle: 0, 0, 64, 64;
       .clip;
       .rgb: 0, 1, 0;
       .rectangle: 0, 0, 64, 64;
       .fill :preserve;
       .rgb: 0, 0, 0;
       .stroke;
       .restore;

       .save;
       .translate: 64, 0;
       .rectangle: 0, 0, 64, 64;
       .clip;
       .rgb: 1, 0, 0;
       .arc: 32, 32, 30, 0, 2 * pi;
       .fill :preserve;
       .rgb: 0, 0, 0;
       .stroke;
       .restore;
   }, 128, 128, Cairo::FORMAT_ARGB32);

my $snake_texture = SDL_CreateTexture( 

   $render,
   %PIXELFORMAT<ARGB8888>,
   STATIC,
   128,
   128

);

SDL_UpdateTexture( 

   $snake_texture,
   SDL_Rect.new(
       :x(0),
       :y(0),
       :w(128),
       :h(128)
   ),
   $snake_image.data,
   $snake_image.stride // 128 * 4

);

SDL_SetTextureBlendMode($snake_texture, 1);

SDL_SetRenderDrawBlendMode($render, 1);

my $snakepiece_srcrect = SDL_Rect.new(:w(64), :h(64)); my $nompiece_srcrect = SDL_Rect.new(:w(64), :h(64), :x(64));

my $event = SDL_Event.new;

enum GAME_KEYS ( 

   K_UP    => 82,
   K_DOWN  => 81,
   K_LEFT  => 80,
   K_RIGHT => 79,

);

my Complex @snakepieces = 10+10i; my Complex @noms; my Complex $snakedir = 1+0i; my $nomspawn = 0; my $snakespeed = 0.1; my $snakestep = 0; my $nom = 4;

my $last_frame_start = now; main: loop { 

   my $start = now;
   my $dt = $start - $last_frame_start // 0.00001;
   while SDL_PollEvent($event) {
       my $casted_event = SDL_CastEvent($event);
       given $casted_event {
           when *.type == QUIT    { last main }
           when *.type == KEYDOWN {
               if GAME_KEYS(.scancode) -> $comm {
                   given $comm {
                       when 'K_LEFT'  { $snakedir = -1+0i unless $snakedir ==  1+0i }
                       when 'K_RIGHT' { $snakedir =  1+0i unless $snakedir == -1+0i }
                       when 'K_UP'    { $snakedir =  0-1i unless $snakedir ==  0+1i }
                       when 'K_DOWN'  { $snakedir =  0+1i unless $snakedir ==  0-1i }
                   }
               }
           }
       }
   }

   if ($nomspawn -= $dt) < 0 {
       $nomspawn += 1;
       @noms.push: (^FIELDW).pick + (^FIELDH).pick * i unless @noms > 3;
       @noms.pop if @noms[*-1] == any(@snakepieces);
   }

   if ($snakestep -= $dt) < 0 {
       $snakestep += $snakespeed;

       @snakepieces.unshift: do given @snakepieces[0] {
           ($_.re + $snakedir.re) % FIELDW
           + (($_.im + $snakedir.im) % FIELDH) * i
       }

       if @snakepieces[2..*].first( * == @snakepieces[0], :k ) -> $idx {
           @snakepieces = @snakepieces[0..($idx + 1)];
       }

       @noms .= grep(
           { $^piece == @snakepieces[0] ?? ($nom += 1) && False !! True }
       );

       if $nom == 0 {
           @snakepieces.pop;
       } else {
           $nom = $nom - 1;
       }
   }

   for @snakepieces {
       SDL_SetTextureColorMod(
           $snake_texture,
           255,
           (cos((++$) / 2) * 100 + 155).round,
           255
       );

       SDL_RenderCopy(
           $render,
           $snake_texture,
           $snakepiece_srcrect,
           SDL_Rect.new(.re * 32, .im * 32, 32, 32)
       );
   }

   SDL_SetTextureColorMod($snake_texture, 255, 255, 255);

   for @noms {
       SDL_RenderCopy(
           $render,
           $snake_texture,
           $nompiece_srcrect,
           SDL_Rect.new(.re * 32, .im * 32, 32, 32)
       )
   }

   SDL_RenderPresent($render);
   SDL_SetRenderDrawColor($render, 0, 0, 0, 0);
   SDL_RenderClear($render);

   $last_frame_start = $start;
   sleep(1 / 50);

}

SDL_Quit();</lang>

Sidef

<lang ruby>class SnakeGame(w, h) { 

   const readkey = frequire('Term::ReadKey')
   const ansi    = frequire('Term::ANSIColor')

   enum (VOID, HEAD, BODY, TAIL, FOOD)

   define (
       LEFT  = [+0, -1],
       RIGHT = [+0, +1],
       UP    = [-1, +0],
       DOWN  = [+1, +0],
   )

   define BG_COLOR    = "on_black"
   define FOOD_COLOR  = ("red"        + " " + BG_COLOR)
   define SNAKE_COLOR = ("bold green" + " " + BG_COLOR)
   define SLEEP_SEC   = 0.02

   const (
       A_VOID  = ansi.colored(' ', BG_COLOR),
       A_FOOD  = ansi.colored('❇', FOOD_COLOR),
       A_BLOCK = ansi.colored('■', SNAKE_COLOR),
   )

   has dir = LEFT
   has grid = [[]]
   has head_pos = [0, 0]
   has tail_pos = [0, 0]

   method init {
       grid = h.of { w.of { [VOID] } }

       head_pos = [h//2, w//2]
       tail_pos = [head_pos[0], head_pos[1]+1]

       grid[head_pos[0]][head_pos[1]] = [HEAD, dir]    # head
       grid[tail_pos[0]][tail_pos[1]] = [TAIL, dir]    # tail

       self.make_food()
   }

   method make_food {
       var (food_x, food_y)

       do {
           food_x = w.rand.int
           food_y = h.rand.int
       } while (grid[food_y][food_x][0] != VOID)

       grid[food_y][food_x][0] = FOOD
   }

   method display {
       print("\033[H", grid.map { |row|
           row.map { |cell|
               given (cell[0]) {
                   when (VOID) { A_VOID }
                   when (FOOD) { A_FOOD }
                   default     { A_BLOCK }
               }
             }.join()
           }.join("\n")
       )
   }

   method move {
       var grew = false

       # Move the head
       var (y, x) = head_pos...

       var new_y = (y+dir[0] % h)
       var new_x = (x+dir[1] % w)

       var cell = grid[new_y][new_x]

       given (cell[0]) {
           when (BODY) { die "\nYou just bit your own body!\n" }
           when (TAIL) { die "\nYou just bit your own tail!\n" }
           when (FOOD) { grew = true; self.make_food()         }
       }

       # Create a new head
       grid[new_y][new_x] = [HEAD, dir]

       # Replace the current head with body
       grid[y][x] = [BODY, dir]

       # Update the head position
       head_pos = [new_y, new_x]

       # Move the tail
       if (!grew) {
           var (y, x) = tail_pos...

           var pos   = grid[y][x][1]
           var new_y = (y+pos[0] % h)
           var new_x = (x+pos[1] % w)

           grid[y][x][0]         = VOID    # erase the current tail
           grid[new_y][new_x][0] = TAIL    # create a new tail

           tail_pos = [new_y, new_x]
       }
   }

   method play {
       STDOUT.autoflush(true)
       readkey.ReadMode(3)

       try {
           loop {
               var key
               while (!defined(key = readkey.ReadLine(-1))) {
                   self.move()
                   self.display()
                   Sys.sleep(SLEEP_SEC)
               }

               given (key) {
                   when ("\e[A") { if (dir != DOWN ) { dir = UP    } }
                   when ("\e[B") { if (dir != UP   ) { dir = DOWN  } }
                   when ("\e[C") { if (dir != LEFT ) { dir = RIGHT } }
                   when ("\e[D") { if (dir != RIGHT) { dir = LEFT  } }
               }
           }
       }
       catch {
           readkey.ReadMode(0)
       }
   }

}

var w = `tput cols`.to_i var h = `tput lines`.to_i

SnakeGame(w || 80, h || 24).play</lang>

Retrieved from "https://rosettacode.org/wiki/Snake?oldid=266715"