Roman Numeral in Php

Welcome to the Roman Numeral in Php page! Here, you'll find the source code for this program as well as a description of how the program works.

Current Solution

<?php

/**
 * Roman numeral string to Decimal value.
 * @param string $romans String to convert.
 * @return int The decimal value.
 * @throws Exception on invalid roman string.
 */
function roman_to_decimal($romans)
{
    // conversion table
    $roman_values = array("I" => 1, "V" => 5, "X" => 10,
        "L" => 50, "C" => 100, "D" => 500, "M" => 1000);

    $total = 0;
    $previous = 0;

    // parse from end to start of string
    for ($i = strlen($romans) - 1; $i >= 0; --$i) {

        // check if the character is a roman numeral
        $numeral = strtoupper($romans[$i]);
        if (!array_key_exists($numeral, $roman_values)) {
            throw new Exception("invalid string of roman numerals");
        }

        // convert to decimal and add/subtract from total.
        $value = $roman_values[$numeral];
        if ($value >= $previous) {
            $total += $value;

        } else {
            $total -= $value;
        }

        // keep track of last value
        $previous = $value;
    }

    return $total;
}

try {

    // Check argument count
    if ($argc < 2) {
        echo "Usage: please provide a string of roman numerals\n";
        exit(1);
    }

    // Convert the string
    echo roman_to_decimal($argv[1]), "\n";
    exit(0);

} catch (Exception $e) {
    echo "Error: ", $e->getMessage(), "\n";
    exit(1);
}

Roman Numeral in Php was written by:

• Jeremy Grifski
• Juan D Frias
• Parker Johansen

If you see anything you'd like to change or update, please consider contributing.

How to Implement the Solution

No 'How to Implement the Solution' section available. Please consider contributing.

How to Run the Solution

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