num-to-text.php

<?php
function convertDigit($digit){
  switch($digit){
    case "0": return "zero";
    case "1": return "one";
    case "2": return "two";
    case "3": return "three";
    case "4": return "four";
    case "5": return "five";
    case "6": return "six";
    case "7": return "seven";
    case "8": return "eight";
    case "9": return "nine";
  }
}

function convertTwoDigits($dig1, $dig2){
  if($dig2 == 0){
    switch($dig1){
      case "1": return "ten";
      case "2": return "twenty";
      case "3": return "thirty";
      case "4": return "forty";
      case "5": return "fifty";
      case "6": return "sixty";
      case "7": return "seventy";
      case "8": return "eighty";
      case "9": return "ninety";
    }
  }
  else if ($dig1 == "1"){
    switch($dig2){
      case "1": return " eleven";
      case "2": return " twelve";
      case "3": return " thirtheen";
      case "4": return " fourteen";
      case "5": return " fifteen";
      case "6": return " sixteen";
      case "7": return " seventeen";
      case "8": return " eighheen";
      case "9": return " nineteen";
    }
  }
  else{
    $temp = convertDigit($dig2);
    switch ($dig1) {
      case "2": return "twenty-$temp";
      case "3": return "thirty-$temp";
      case "4": return "forty-$temp";
      case "5": return "fifty-$temp";
      case "6": return "sixty-$temp";
      case "7": return "seventy-$temp";
      case "8": return "eighty-$temp";
      case "9": return "ninety-$temp";
    }
  }
}

function convertThreeDigit($dig1, $dig2, $dig3){
    $output = "";
    if($dig1 == "0" && $dig2 == "0" && $dig3 == "0") return "";

    if($dig1 == "0"){$output .=" ". convertTwoDigits($dig2, $dig3);}

    if($dig1 != "0"){
      $output .= convertDigit($dig1)." hundred";
      if($dig2 != "0" || $dig3 != "0") $output .= " and";
    }

    if($dig2 != "0") $output .=" ". convertTwoDigits($dig2, $dig3);
    else if($dig3 != "0"){$output .= " ".convertDigit($dig3);}

    return $output;
}

function convertGroup($index){
  switch ($index) {
    case 0: return "";
    case 1: return "thousand";
    case 2: return "million";
    case 3: return "billion";
    case 4: return "trillion";
    case 5: return "quadrillion";
    case 6: return "quintrillion";
    case 7: return "sextillion";
    case 8: return "septillion";
    case 9: return "octillion";
    case 10: return "nonillion";
    case 11: return "decillion";
  }
}

function convertNumber($num){
    $dec = strpos($num, '.');
    if($dec !== false){
         list($num, $dec) = explode('.', $num);
    }
    else{
        $dec = 0;
    }
  $output = "";
  if($num{0} == "-"){
    $output .= "negative ";
    $num = ltrim($num, '-');
  }
  else if($num{0} == "+"){
    $output .= "positive ";
    $num = ltrim($num, '+');
  }

  if($num{0} == "0"){
    $output .= " zero";
  }
  else{
    $num = str_pad($num, 36, "0", STR_PAD_LEFT);
    $group = rtrim(chunk_split($num, 3, " "), " ");
    $groups = explode(" ",$group);

    $groups2 = array();
    foreach($groups as $g){
      $groups2[] = convertThreeDigit($g{0}, $g{1}, $g{2});
    }

    for($z=0;$z<count($groups2);$z++){
      if($groups2[$z] != ""){
        $output .= $groups2[$z].convertGroup(11-$z).(
          ($z < 11) &&
          (!array_search("", array_slice($groups2, $z+1, -1))) &&
          ($groups2[11] != "") &&
          ($groups[11]{0} == '0')
          ? " and " : ", ");
      }
    }

    $output = rtrim($output, ", ");
  }

  if($dec > 0){
    $output .= " point";
    for($i=0;$i<strlen($dec);$i++){
      $output .= " ".convertDigit($dec[$i]);
    }
  }
  return $output;
}

if(count($argv) < 2){
    echo "Incomplete command. Usage is 'php num_to_text.php' number_to_convert";
}
else{
    echo convertNumber($argv[1]);
}