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Hello,

I am attempting to develop a simple php script which will generate a 4 letter sequence when a button is pressed. However the sequence has a few rules it has to follow.

For example:

the letters have to be A B C D E F G H J K L M P Q and R

The second letter must be a letter AFTER the first

The fourth letter must be a letter AFTER the third

There can't be 2 of the same number.

 

I am a bit confused on how I will do this as I am quite new to php, I though about generating the first as $1, then generating the second as $2, then if $1 > $2, then I would regenerate $2 until it wasn't. Then repeating that for $4.

 

However I am not sure on the coding which would be involved in doing this.

 

If someone could give me a few pointers or a link to a website which would help me it would be much appreciated.

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the first would have to leave room for the other 3... so it's possibilities would be

 

A B C D E F G H J K L M

 

then seconds possibilities would be from (exclusive) the first letter to (inclusive) P

then thirds possibilities would be from (exclusive) the second letter to (inclusive) Q

then fourths possibilities would be from (exclusive) the third letter to (inclusive) R

 

you could use an array or just a string... using random to find the position of the letter to use, save that letter... as well as the position so you can create a substring or portion of the array to do the next random... etc

$ltrs = "ABCDEFGHJKLMPQR";

$one = rand(0, strlen($ltrs)-2);
$str = $ltrs[$one];
$ltrs = substr($ltrs, 0, $one).substr($ltrs, $one+1); // remove this letter, it can't be used again

$two = rand($one, strlen($ltrs)-1); // must come after $one
$str .= $ltrs[$two];
$ltrs = substr($ltrs, 0, $two).substr($ltrs, $two+1); // remove this letter, it can't be used again

$three = rand(0, strlen($ltrs)-2);
$str = $ltrs[$three];
$ltrs = substr($ltrs, 0, $three).substr($ltrs, $three+1); // remove this letter, it can't be used again

$four = rand($three, strlen($ltrs)-1); // must come after $three
$str .= $ltrs[$four];
return $str;

I think I may need to learn a bit more for this.

Thankyou very much for the code, I tried to implement it into a page using

 

<?php
$ltrs = "ABCDEFGHJKLMPQRS";
$name = $_POST['name'];

$one = rand(0, strlen($ltrs)-2);
$str = $ltrs[$one];
$ltrs = substr($ltrs, 0, $one).substr($ltrs, $one+1); // remove this letter, it can't be used again

$two = rand($one, strlen($ltrs)-1); // must come after $one
$str .= $ltrs[$two];
$ltrs = substr($ltrs, 0, $two).substr($ltrs, $two+1); // remove this letter, it can't be used again

$three = rand(0, strlen($ltrs)-2);
$str = $ltrs[$three];
$ltrs = substr($ltrs, 0, $three).substr($ltrs, $three+1); // remove this letter, it can't be used again

$four = rand($three, strlen($ltrs)-1); // must come after $three
$str .= $ltrs[$four];
return $str;

$code = $one.$two.$three.$four;
?>

<html>
<head>
<title>Random Code Generator</title>
</head>
<body>
<?php
echo "Ref. Name:" .$name. "<br />"; // prints name
echo "Code:" .$code. "<br />"; // prints code
?>
</body>
</html>

$name is a variable from a form which is connected to the php doc.

 

But the page just returned blank. Any more help would be very much appreciated.

Sorry for any nooby mistakes I may have made.

 

Ooops, little typo. Try now.

 

$ltrs = "ABCDEFGHJKLMPQRS";
$name = $_POST['name'];

$one = rand(0, strlen($ltrs)-2);
$str = $ltrs[$one];
$ltrs = substr($ltrs, 0, $one).substr($ltrs, $one+1); // remove this letter, it can't be used again

$two = rand($one, strlen($ltrs)-1); // must come after $one
$str .= $ltrs[$two];
$ltrs = substr($ltrs, 0, $two).substr($ltrs, $two+1); // remove this letter, it can't be used again

$three = rand(0, strlen($ltrs)-2);
$str .= $ltrs[$three];
$ltrs = substr($ltrs, 0, $three).substr($ltrs, $three+1); // remove this letter, it can't be used again

$four = rand($three, strlen($ltrs)-1); // must come after $three
$str .= $ltrs[$four];

echo $str;

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