Incrementing With Numbers and Letters

[Pryach]

I'm not entirely sure how to describe this but I'll do my best.

I'm trying to figure out how to make a loop that would print a number, do a link break, increment the number then print another number. The problem I face is I want to add in letters. So it would go 0 - 9, then a - z. Then 00 to 09 to 0z. Then 10 to 19 to 1z. etc. Eventually getting to zzz or however many places I wanted it to go.

Can anyone help me out with this?

[jazz_snob]

The only catch is when you have to carry the '1'. You can't go z -> 0z, but z -> 1z makes sense. I prefer object-oriented, test-first solns. Here is what I got:

<?php

class NewMathCounter
{
        /** This is an array, the values you'll use to count with */
	var $_base;
	var $_value;

function NewMathCounter( $base, $value = null )
{
	$this -> _base = $base;
	$this -> _value = array();
	if( $value == null )
	{
		$this -> _value[ 0 ] = $this -> _base[ 0 ];
	}
	else
	{
		$this -> _value = $this -> _parse( $value );
	}
}

function _parse( $string )
{
	$len = strlen( $string );
	$retVal = array();
	$i = $len;
	while( $i > 0 )
	{
		$retVal[] = substr( $string, $i - 1, 1 );
		$i -= 1;
	}
	return $retVal;
}

function increment( )
{
	//look at rightmost char, _value[ 0 ]
	$col = 0;
	$this -> _value[ $col ] = $this -> _incrementColumn( $this -> _value[ $col ] );
	//if we get back a zero, then we need to carry the one!!!
	while( $this -> _value[ $col ] == "0" )
	{
		$col += 1;
		if( !isset( $this -> _value[ $col ] ) )
		{
			$this -> _value[ $col ] = $this -> _base[ 1 ];
		}
		else
		{
			$this -> _value[ $col ] = $this -> _incrementColumn( $this -> _value[ $col ] );
		}
	}
}

function _incrementColumn( $currentValue )
{
	$index = array_search( $currentValue, $this -> _base );
	if( $index < sizeof( $this -> _base ) - 1 )
	{
		return $this -> _base[ $index + 1 ];
	}
	return 0;
}

function getBase()
{
	return sizeof( $this -> _base );
}

function toString()
{
	$string = "";
	for( $i = sizeof( $this -> _value ) - 1; $i >= 0; $i -= 1 )
	{
		$string .= $this -> _value[ $i ];
	}
	return $string;
}
}

?>

I think if you look at my simpletest unit test you'll understand how to use this...

<?php

error_reporting( E_ALL );

if (!defined('SIMPLE_TEST')) 
{
	define('SIMPLE_TEST', '/usr/local/simpletest/');
}
require_once(SIMPLE_TEST . 'unit_tester.php');
require_once(SIMPLE_TEST . 'reporter.php');

require_once '../repo/init.php';
require_once 'NewMathCounter.php';


class NewMathCounter_Test extends UnitTestCase 
{
	var $arr;

function NewMathCounter_Test() 
{
	$this->UnitTestCase();
	$this -> arr = array( '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 
						  'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
						  'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
						  'u', 'v', 'w', 'x', 'y', 'z' );
}

function test_get_base()
{
	$counter =& new NewMathCounter( $this -> arr );
	$this -> assertEqual( 36,  $counter -> getBase() );
}

function test_get_first()
{
	$counter =& new NewMathCounter( $this -> arr );
	$this -> assertEqual( "0", $counter -> toString() );
}

function test_increment()
{
	$counter =& new NewMathCounter( $this -> arr );
	$counter -> increment();
	$this -> assertEqual( "1", $counter -> toString() );
}

function test_initial_value()
{
	$counter =& new NewMathCounter( $this -> arr, "1z" );
	$this -> assertEqual( "1z", $counter -> toString(), "got back " . $counter -> toString() );
	$counter =& new NewMathCounter( $this -> arr, "4zff" );
	$this -> assertEqual( "4zff", $counter -> toString(), "returned " . $counter -> toString() );
	$counter =& new NewMathCounter( $this -> arr, "9" );
	$counter -> increment();
	$this -> assertEqual( "a", $counter -> toString(), "returned " . $counter -> toString() );

}

function test_roll()
{
	$counter =& new NewMathCounter( $this -> arr, "z" );
	$this -> assertEqual( "z", $counter -> toString() );
	$counter -> increment();
	$this -> assertEqual( "10", $counter -> toString(), "returned: " . $counter -> toString() );
	//lets increment it...
	$counter -> increment();
	$this -> assertEqual( "11", $counter -> toString(), "returned: " . $counter -> toString() );
}

function test_roll_again()
{
	$counter =& new NewMathCounter( $this -> arr, "zz" );
	$counter -> increment();
	$this -> assertEqual( "100", $counter -> toString(), "returned: " . $counter -> toString() );
	//add one
	$counter -> increment();
	$this -> assertEqual( "101", $counter -> toString(), "returned: " . $counter -> toString() );
}

function test_printing()
{
	$counter =& new NewMathCounter( $this -> arr );
	for( $i = 1; $i < 1000; $i += 1 )
	{
		$counter -> increment();
		echo "<br />" . $counter -> toString();
	}
}

}

$test = &new NewMathCounter_Test();
$test -> run( new HtmlReporter() );	
?>

🆒

[jazz_snob]

Made minor modifications. I think you can 'count' w/ any 2 or more characters using this thing.

<?php

class NewMathCounter
{
	/** an array of the chars you want to count with, must have at least 2 elements */
	var $_base;
	var $_value;

/** Optionally you can set initial value with $value arg.  I don't check $value to see if its 'valid' */
function NewMathCounter( $base, $value = null )
{
	$this -> _base = $base;
	$this -> _value = array();
	if( $value == null )
	{
		$this -> _value[ 0 ] = $this -> _base[ 0 ];
	}
	else
	{
		$this -> _value = $this -> _parse( $value );
	}
}

function _parse( $string )
{
	$len = strlen( $string );
	$retVal = array();
	$i = $len;
	while( $i > 0 )
	{
		$retVal[] = substr( $string, $i - 1, 1 );
		$i -= 1;
	}
	return $retVal;
}

function increment( )
{
	//look at rightmost char, _value[ 0 ]
	$col = 0;
	$this -> _value[ $col ] = $this -> _incrementColumn( $this -> _value[ $col ] );
	//if we get back _base[ 0 ], then we need to 'carry the one' which is _base[ 1 ]
	while( $this -> _value[ $col ] == $this -> _base[ 0 ] )
	{
		$col += 1;
		if( !isset( $this -> _value[ $col ] ) )
		{
			$this -> _value[ $col ] = $this -> _base[ 1 ];
		}
		else
		{
			$this -> _value[ $col ] = $this -> _incrementColumn( $this -> _value[ $col ] );
		}
	}
}

function _incrementColumn( $currentValue )
{
	$index = array_search( $currentValue, $this -> _base );
	if( $index < sizeof( $this -> _base ) - 1 )
	{
		return $this -> _base[ $index + 1 ];
	}
	return $this -> _base[ 0 ];
}

function getBase()
{
	return sizeof( $this -> _base );
}

function toString()
{
	$string = "";
	for( $i = sizeof( $this -> _value ) - 1; $i >= 0; $i -= 1 )
	{
		$string .= $this -> _value[ $i ];
	}
	return $string;
}
}

?>