Decimal to Roman Numeral Conversion

John — Thu, 21 May 2009 06:07:44 +0000

#include <iostream>
#include <string>
using namespace std;

string dec_to_numeral(int x) {
    int dec[13] = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};
    string num[13] = {"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"};
    string numeral;

    for(int i = 0; i < 13; i++) {
        while (x >= dec[i]) {
            x -= dec[i];
            numeral.append(num[i]);
        }
    }

    return numeral;
}

int main() {
    //example
    cout << dec_to_numeral(400);

    return 0;
}

Binary to Decimal Conversion

John — Thu, 21 May 2009 05:08:00 +0000

Converts a binary number to its decimal equivalent. However unlike the bindec function, this will preserve the binary/radix point.

Code



/**
 * Convert a binary number with our without
 * a radix point to its decimal equivalent.
 *
 * @param $binary The binary number to convert.
 * @param $output Show the calculations.
 * @return The decimal conversion
 */
function bin2dec($binary, $output = false) {
    $N = 0;
    $o = "";
    list ( $rhs, $lhs ) = explode ( ".", $binary );
    $rhs = strrev ( $rhs );
    for($i = 0; $i < strlen ( $rhs ); $i ++) {
        $d = $rhs [$i] * pow ( 2, $i );
        $N = $d + $N;
        $o = ($d == 0) ? $o : $o . $d . " + ";
    }

    for($i = 0; $i < strlen ( $lhs ); $i ++) {
        $d = $lhs [$i] * pow ( 2, - ($i + 1) );
        $N = $d + $N;
        $o = ($d == 0) ? $o : $o . $d . " + ";
    }

    return ($output) ? substr ( $o, 0, - 3 ) . " = " . $N : $N;
}

?>

Usage

echo bin2dec ( "1011101.1000101", true );

Output

1 + 4 + 8 + 16 + 64 + 0.5 + 0.03125 + 0.0078125 = 93.5390625

Usage

echo bin2dec ( "1011101.1000101");

Output

93.5390625

Permutations

John Ciacia » decimal

Decimal to Roman Numeral Conversion

Binary to Decimal Conversion