Indian currency numeric to words conversion

inr-numeric-words.php

<?php
function convertToIndianCurrencyWords($number) {
    $ones = array(
        0 => '', 1 => 'One', 2 => 'Two', 3 => 'Three', 4 => 'Four',
        5 => 'Five', 6 => 'Six', 7 => 'Seven', 8 => 'Eight', 9 => 'Nine'
    );

    $teens = array(
        11 => 'Eleven', 12 => 'Twelve', 13 => 'Thirteen', 14 => 'Fourteen',
        15 => 'Fifteen', 16 => 'Sixteen', 17 => 'Seventeen', 18 => 'Eighteen',
        19 => 'Nineteen'
    );

    $tens = array(
        1 => 'Ten', 2 => 'Twenty', 3 => 'Thirty', 4 => 'Forty', 5 => 'Fifty',
        6 => 'Sixty', 7 => 'Seventy', 8 => 'Eighty', 9 => 'Ninety'
    );

    $hundreds = array(
        '', 'Hundred', 'Thousand', 'Lakh', 'Crore'
    );

    $words = array();

    if ($number < 0) {
        $words[] = 'Minus';
        $number = abs($number);
    }

    $numString = (string)$number;

    $numDigits = strlen($numString);
    $numChunks = ceil($numDigits / 2);
    $numChunkLen = $numDigits % 2 ?: 2;
    $numChunkPos = 0;

    for ($i = 0; $i < $numChunks; ++$i) {
        $numChunk = substr($numString, $numChunkPos, $numChunkLen);
        $numChunk = (int)$numChunk;

        if ($numChunk != 0) {
            $numChunkWords = array();

            if ($numChunk >= 10 && $numChunk <= 19) {
                $numChunkWords[] = $teens[$numChunk];
            } elseif ($numChunk >= 20) {
                $tensDigit = (int)($numChunk / 10);
                $numChunkWords[] = $tens[$tensDigit];

                $onesDigit = $numChunk % 10;
                if ($onesDigit != 0) {
                    $numChunkWords[] = $ones[$onesDigit];
                }
            } elseif ($numChunk != 0) {
                $numChunkWords[] = $ones[$numChunk];
            }

            if (!empty($numChunkWords)) {
                $words = array_merge($words, $numChunkWords);
                if ($numChunkPos > 0) {
                    $words[] = $hundreds[$i];
                }
            }
        }

        $numChunkPos += $numChunkLen;
        $numChunkLen = 2;
    }

    return implode(' ', $words);
}

$number = 123456789; // Example number
$words = convertToIndianCurrencyWords($number);

echo ucfirst($words) . ' Rupees Only'; // Output: Twelve Crore Thirty Four Lakh Fifty Six Thousand Seven Hundred Eighty Nine Rupees Only
?>