Online PHP editor | refs for EBDGF

<?php namespace JoshDiFabio; interface RomanNumeralGeneratorInterface { /** * @param int $number * @return string * @throws \InvalidArgumentException Argument not an integer or out of range * @author Josh Di Fabio <joshdifabio@hotmail.com> */ public function generate($number); } class RomanNumeral { const ONE = 'I'; const FIVE = 'V'; const TEN = 'X'; const FIFTY = 'L'; const ONE_HUNDRED = 'C'; const FIVE_HUNDRED = 'D'; const ONE_THOUSAND = 'M'; } class RomanNumeralGenerator implements RomanNumeralGeneratorInterface { /** * @var array * @author Josh Di Fabio <joshdifabio@hotmail.com> */ private $_numerals = array( array( 'integer' => 1000, 'symbol' => RomanNumeral::ONE_THOUSAND, ), array( 'integer' => 500, 'symbol' => RomanNumeral::FIVE_HUNDRED, ), array( 'integer' => 100, 'symbol' => RomanNumeral::ONE_HUNDRED, ), array( 'integer' => 50, 'symbol' => RomanNumeral::FIFTY, ), array( 'integer' => 10, 'symbol' => RomanNumeral::TEN, ), array( 'integer' => 5, 'symbol' => RomanNumeral::FIVE, ), array( 'integer' => 1, 'symbol' => RomanNumeral::ONE, ), ); /** * @param int $number * @return string * @throws \InvalidArgumentException Argument not an integer or out of range * @author Josh Di Fabio <joshdifabio@hotmail.com> */ public function generate($number) { if (!is_integer($number)) { throw new \InvalidArgumentException('Provided argument is not an integer.'); } if (1 > $number || 3999 < $number) { throw new \InvalidArgumentException( 'The provided number is not within the allowed range of 1 to 3999.'); } $numerals = array(); while (0 < $number) { // loop through numerals from largest to smallest foreach ($this->_numerals as $_numeralIdx => &$_numeralData) { /* * if the input number less any already selected numerals is larger than the current * numeral, choose the current numeral and deduct its integer value from the input * number */ if ($number >= $_numeralData['integer']) { $numerals[] = $_numeralData['symbol']; $number -= $_numeralData['integer']; break; } $_lesserNumeralData = $this->_numerals[1 + $_numeralIdx]; if ($number >= $_numeralData['integer'] - $_lesserNumeralData['integer']) { $numerals[] = $_lesserNumeralData['symbol']; $number -= $_lesserNumeralData['integer']; $numerals[] = $_numeralData['symbol']; $number -= $_numeralData['integer']; break; } } } return implode('', $numerals); } } $generator = new RomanNumeralGenerator; echo $generator->generate(3999);