BattleShip – Game

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This is the classic game of battleship.

Head Code:

<style type="text/css">
.intro { font-size:10pt; font-style:italic }
.heading { font-size:14pt; font-weight:bold; font-family:sans-serif }
.title { font-size:18pt; font-weight:bold; background-color:navy; color:white; text-align:center; font-family:sans-serif }
</style>

Body Code:

<SCRIPT LANGUAGE="JavaScript">
<!-- Begin
/* Information used to draw the ships
*/
var ship =  [[[1,5], [1,2,5], [1,2,3,5], [1,2,3,4,5]], [[6,10], [6,7,10], [6,7,8,10], [6,7,8,9,10]]];

/* Information used to draw sunk ships
*/
var dead = [[[201,203], [201,202,203], [201,202,202,203], [201,202,202,202,203]], [[204,206], [204,205,206], [204,205,205,206], [204,205,205,205,206]]];

/* Information used to describe ships
*/
var shiptypes = [["Minesweeper",2,4],["Frigate",3,4],[ "Cruiser",4,2],[ "Battleship",5,1]];

var gridx = 16, gridy = 16;
var player = [], computer = [], playersships = [], computersships = [];
var playerlives = 0, computerlives = 0, playflag=true, statusmsg="";

/* Function to preload all the images, to prevent delays during play
*/
var preloaded = [];
function imagePreload() {
var i,ids = [1,2,3,4,5,6,7,8,9,10,100,101,102,103,201,202,203,204,205,206];
window.status = "Preloading images...please wait";
for (i=0;i<ids.length;++i) {
var img = new Image, name = "http://www.js-examples.com/data/ex_12/batt"+ids[i]+".gif";
img.src = name;
preloaded[i] = img;
}
window.status = "";
}

/* Function to place the ships in the grid
*/
function setupPlayer(ispc) {
var y,x;
grid = [];
for (y=0;y<gridx;++y) {
grid[y] = [];
for (x=0;x<gridx;++x)
grid[y][x] = [100,-1,0];
}

var shipno = 0;
var s;
for (s=shiptypes.length-1;s>=0;--s) {
var i;
for (i=0;i<shiptypes[s][2];++i) {
var d = Math.floor(Math.random()*2);
var len = shiptypes[s][1], lx=gridx, ly=gridy, dx=0, dy=0;
if ( d==0) {
lx = gridx-len;
dx=1;
}
else {
ly = gridy-len;
dy=1;
}
var x,y,ok;
do {
y = Math.floor(Math.random()*ly);
x = Math.floor(Math.random()*lx);
var j,cx=x,cy=y;
ok = true;
for (j=0;j<len;++j) {
if (grid[cy][cx][0] < 100) {
ok=false;
break;
}
cx+=dx;
cy+=dy;
   }
} while(!ok);
var j,cx=x,cy=y;
for (j=0;j<len;++j) {
grid[cy][cx][0] = ship[d][s][j];
grid[cy][cx][1] = shipno;
grid[cy][cx][2] = dead[d][s][j];
cx+=dx;
cy+=dy;
}
if (ispc) {
computersships[shipno] = [s,shiptypes[s][1]];
computerlives++;
}
else {
playersships[shipno] = [s,shiptypes[s][1]];
playerlives++;
}
shipno++;
   }
}
return grid;
}

/* Function to change an image shown on a grid
*/
function setImage(y,x,id,ispc) {
if ( ispc ) {
computer[y][x][0] = id;
document.images["pc"+y+"_"+x].src = "http://www.js-examples.com/data/ex_12/batt"+id+".gif";
}
else {
player[y][x][0] = id;
document.images["ply"+y+"_"+x].src = "http://www.js-examples.com/data/ex_12/batt"+id+".gif";
   }
}

/* Function to insert HTML source for a grid
*/
function showGrid(ispc) {
var y,x;
for (y=0;y<gridy;++y) {
for (x=0;x<gridx;++x) {
if ( ispc )
document.write ('<a href="javascript:gridClick('+y+','+x+');"><img name="pc'+y+'_'+x+'" src="http://www.js-examples.com/data/ex_12/batt100.gif" width=16 height=16></a>');
else
document.write ('<a href="javascript:void(0);"><img name="ply'+y+'_'+x+'" src="/data/ex_12/batt'+player[y][x][0]+'.gif" width=16 height=16></a>');
}
document.write('<br>');
   }
}

/* Handler for clicking on the grid
*/
function gridClick(y,x) {
if ( playflag ) {
if (computer[y][x][0] < 100) {
setImage(y,x,103,true);
var shipno = computer[y][x][1];
if ( --computersships[shipno][1] == 0 ) {
sinkShip(computer,shipno,true);
alert("You sank my "+shiptypes[computersships[shipno][0]][0]+"!");
updateStatus();
if ( --computerlives == 0 ) {
alert("You win! Press the Refresh button onn"+
"your browser to play another game.");
playflag = false;
}
   }
if ( playflag ) computerMove();
}
else if (computer[y][x][0] == 100) {
setImage(y,x,102,true);
computerMove();
      }
   }
}

/* Function to make the computers move. Note that the computer does not cheat, oh no!
*/
function computerMove() {
var x,y,pass;
var sx,sy;
var selected = false;

/* Make two passes during 'shoot to kill' mode
*/
for (pass=0;pass<2;++pass) {
for (y=0;y<gridy && !selected;++y) {
for (x=0;x<gridx && !selected;++x) {
/* Explosion shown at this position
*/
if (player[y][x][0]==103) {
sx=x; sy=y;
var nup=(y>0 && player[y-1][x][0]<=100);
var ndn=(y<gridy-1 && player[y+1][x][0]<=100);
var nlt=(x>0 && player[y][x-1][0]<=100);
var nrt=(x<gridx-1 && player[y][x+1][0]<=100);
if ( pass == 0 ) {
/* On first pass look for two explosions
   in a row - next shot will be inline
*/
var yup=(y>0 && player[y-1][x][0]==103);
var ydn=(y<gridy-1 && player[y+1][x][0]==103);
var ylt=(x>0 && player[y][x-1][0]==103);
var yrt=(x<gridx-1 && player[y][x+1][0]==103);
if ( nlt && yrt) { sx = x-1; selected=true; }
else if ( nrt && ylt) { sx = x+1; selected=true; }
else if ( nup && ydn) { sy = y-1; selected=true; }
else if ( ndn && yup) { sy = y+1; selected=true; }
}
else {
/* Second pass look for single explosion - 
   fire shots all around it
*/
if ( nlt ) { sx=x-1; selected=true; }
else if ( nrt ) { sx=x+1; selected=true; }
else if ( nup ) { sy=y-1; selected=true; }
else if ( ndn ) { sy=y+1; selected=true; }
            }
         }
      }
   }
}
if ( !selected ) {
/* Nothing found in 'shoot to kill' mode, so we're just taking
   potshots. Random shots are in a chequerboard pattern for 
   maximum efficiency, and never twice in the same place
*/
do{
sy = Math.floor(Math.random() * gridy);
sx = Math.floor(Math.random() * gridx/2)*2+sy%2;
} while( player[sy][sx][0]>100 );
}
if (player[sy][sx][0] < 100) {
/* Hit something
*/
setImage(sy,sx,103,false);
var shipno = player[sy][sx][1];
if ( --playersships[shipno][1] == 0 ) {
sinkShip(player,shipno,false);
alert("I sank your "+shiptypes[playersships[shipno][0]][0]+"!");
if ( --playerlives == 0 ) {
knowYourEnemy();
alert("I win! Press the Refresh button onn"+
"your browser to play another game.");
playflag = false;
      }
   }
}
else {
/* Missed
*/
setImage(sy,sx,102,false);
   }
}

/* When whole ship is hit, show it using changed graphics
*/
function sinkShip(grid,shipno,ispc) {
var y,x;
for (y=0;y<gridx;++y) {
for (x=0;x<gridx;++x) {
if ( grid[y][x][1] == shipno )
if (ispc) setImage(y,x,computer[y][x][2],true);
else setImage(y,x,player[y][x][2],false);
      }
   }
}

/* Show location of all the computers ships - when player has lost
*/
function knowYourEnemy() {
var y,x;
for (y=0;y<gridx;++y) {
for (x=0;x<gridx;++x) {
if ( computer[y][x][0] == 103 )
setImage(y,x,computer[y][x][2],true);
else if ( computer[y][x][0] < 100 )
setImage(y,x,computer[y][x][0],true);
      }
   }
}

/* Show how many ships computer has left
*/
function updateStatus() {
var f=false,i,s = "Computer has ";
for (i=0;i<computersships.length;++i) {
if (computersships[i][1] > 0) {
if (f) s=s+", "; else f=true;
s = s + shiptypes[computersships[i][0]][0];
   }
}
if (!f) s = s + "nothing left, thanks to you!";
statusmsg = s;
window.status = statusmsg;
}
function setStatus() {
window.status = statusmsg;
}
/* Start the game!
*/
imagePreload();
player = setupPlayer(false);
computer = setupPlayer(true);
document.write("<center><table><tr><td align=center><p class='heading'>COMPUTER'S FLEET</p></td>"+
"<td align=center><p class='heading'>PLAYER'S FLEET</p></td></tr><tr><td>");
showGrid(true);
document.write("</td><td>");
showGrid(false);
document.write("</td></tr></table></center>");
updateStatus();
setInterval("setStatus();", 500);

document.write("<BR><center>Images->");
for(var i=0;i<preloaded.length;i++)
  document.write("<img src="+preloaded[i].src+"> ");
document.write("</center>");
//  End -->
</script>

Times Viewed: 16

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