Generate random player strengths in a pyramid structure (PHP)

Question

For an online game (MMORPG) I want to create characters (players) with random strength values. The stronger the characters are, the less should exist of this sort.

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Answer 1

It's probably easiest to use percentages in this case.

From your examples would approximately be (converted to an array for ease of use later):

$strength[1] = .3;  // start with a key of 1
$strength[2] = .26;
$strength[3] = .21;
$strength[4] = .15;
$strength[5] = .08;

That way, you can generate a random number using mt_rand() and divide by the maximum possible value to get a number between 0 and 1:

$rand = mt_rand() / mt_getrandmax(); // rand is some random value between 0 and 1

Then you can use a foreach statement to isolate each case:

$comparisonPercentage = 1;
$selectedLevel = count($strength); // covers the case where mt_rand() returns 0
foreach($strength as $level => $currentPercentage) 
{
    $comparisonPercentage -= $currentPercentage;
    if ($rand >  $comparisonPercentage) 
    {
        $selectedLevel = $level;
        break;
    }
}

// $selectedLevel contains the level you need...

If you do it this way, you only have to change the $strength array if you need to fiddle with the percentages.