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Selecting Random Numbers- source

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Published on: Saturday 29th November 1997 By: Martin Webb
lottery.htm

<HTML>
<HEAD>

<SCRIPT LANGUAGE="JavaScript"><!--
function makeArray() {
    this[0] = makeArray.arguments.length;
    for (i = 0; i<makeArray.arguments.length; i++)
        this[i+1] = makeArray.arguments[i];
}

var colors = new makeArray('aliceblue','antiquewhite','aqua','aquamarine','azure',
                           'beige','blanchedalmond','blue','blueviolet','brown','burlywood',
                           'cadetblue','chartreuse','chocolate','coral','cornflowerblue',
                           'cornsilk','crimson','cyan','darkblue','darkcyan','darkgoldenrod',
                           'darkgray','darkgreen','darkkhaki','darkmagenta','darkolivegreen',
                           'darkorange','darkorchid','darkred','darksalmon','darkseagreen',
                           'darkslateblue','darkslategray','darkturquoise','darkviolet',
                           'deeppink','deepskyblue','dimgray','dodgerblue','floralwhite',
                           'forestgreen','fuchsia','gainsboro','ghostwhite','gold','goldenrod',
                           'gray','green','greenyellow','honeydew','hotpink','indianred',
                           'ivory','khaki','lavender','lavenderblush','lawngreen',
                           'lemonchiffon','lightblue','lightblue','lightcoral','lightcyan',
                           'lightgoldenrodyellow','lightgreen','lightgrey','lightpink',
                           'lightsalmon','lightseagreen','lightskyblue','lightslategray',
                           'lightsteelblue','lightyellow','lime','limegreen','linen','magenta',
                           'maroon','mediumaquamarine','mediumblue','mediumorchid',
                           'mediumpurple','mediumseagreen','mediumslateblue',
                           'mediumspringgreen','mediumturquoise','mediumvioletred',
                           'midnightblue','mintcream','mistyrose','moccasin','navajowhite',
                           'navy','oldlace','olive','olivedrab','orange','orangered','orchid',
                           'palegoldenrod','palegreen','paleturquoise','palevioletred',
                           'papayawhip','peachpuff','peru','pink','plum','powderblue','purple',
                           'red','rosybrown','royalblue','saddlebrown','salmon','sandybrown',
                           'seagreen','seashell','sienna','silver','skyblue','slateblue',
                           'slategray','snow','springgreen','steelblue','tan','teal','thistle',
                           'tomato','turquoise','violet','wheat','white','whitesmoke','yellow',
                           'yellowgreen');

function MakeEmptyArray(size) {
    this[0] = size;
    for (i = 1; i <= size; i++)
        this[i] = '';
}

function ResetLotteryBalls() {
    for (var i = 1; i <= lotterynumbers[0]; i++)
        lotterynumbers[i] = '';
}
 
function SelectLotteryBalls(number) {
    while (number > 0) {
        random = rand(lotterynumbers[0]);
        if (lotterynumbers[random] == '') {
            lotterynumbers[random] = 'X';
            number--;
        }
    }
}

function ShowLotteryBalls() {
    document.write('<P>');
    for (var i=1; i <= lotterynumbers[0]; i++) {
        if (lotterynumbers[i] != '')
            document.write('  <IMG SRC="balls/'+i+'.gif" HEIGHT=50 WIDTH=50 ALT="' + i +'">  ');
    }
}

//--></SCRIPT>

<SCRIPT>
<!--
// The Central Randomizer 1.3 (C) 1997 by Paul Houle (houle@msc.cornell.edu)
// See:  http://www.msc.cornell.edu/~houle/javascript/randomizer.html

rnd.today=new Date();
rnd.seed=rnd.today.getTime();

function rnd() {
        rnd.seed = (rnd.seed*9301+49297) % 233280;
         return rnd.seed/(233280.0);
};

function rand(number) {
        return Math.ceil(rnd()*number);
};

// end central randomizer. -->

</SCRIPT>

</HEAD>

<BODY><CENTER>

<SCRIPT LANGUAGE="JavaScript"><!--
var lotteryballs = 49;
var ballstoselect = 6;

var lotterynumbers = new MakeEmptyArray(lotteryballs);

document.write('A selection of random lottery numbers<BR>');

var color = colors[rand(colors[0])];

document.write('<TABLE BGCOLOR="' + color + '"><TR><TD ALIGN="CENTER" HEIGHT="100">');
ResetLotteryBalls();SelectLotteryBalls(ballstoselect);ShowLotteryBalls();
document.write('<\/TD><\/TD><\/TABLE>');
//--></SCRIPT>

<A HREF="index.htm" TARGET="_parent">Return</A>

</CENTER></BODY>
</HTML>
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