本文实例讲述了php实现阿拉伯数字和罗马数字相互转换的方法。分享给大家供大家参考。具体如下:
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<?php
// Function that calculates the roman string to the given number:
function dec2roman( $f )
{
// Return false if either $f is not a real number,
//$f is bigger than 3999 or $f is lower or equal to 0:
if (! is_numeric ( $f ) || $f > 3999 || $f <= 0) return false;
// Define the roman figures:
$roman = array (
'M' => 1000,
'D' => 500,
'C' => 100,
'L' => 50,
'X' => 10,
'V' => 5,
'I' => 1
);
// Calculate the needed roman figures:
foreach ( $roman as $k => $v )
if (( $amount [ $k ] = floor ( $f / $v )) > 0)
$f -= $amount [ $k ] * $v ;
// Build the string:
$return = '' ;
foreach ( $amount as $k => $v )
{
$return .= $v <= 3 ? str_repeat ( $k , $v ) : $k . $old_k ;
$old_k = $k ;
}
// Replace some spacial cases and return the string:
return str_replace ( array ( 'VIV' , 'LXL' , 'DCD' ), array ( 'IX' , 'XC' , 'CM' ), $return );
}
// echo dec2romen(1981);
// Function to get the decimal value of a roman string:
function roman2dec( $str = '' )
{
// Return false if not at least one letter is in the string:
if ( is_numeric ( $str )) return false;
// Define the roman figures:
$roman = array (
'M' => 1000,
'D' => 500,
'C' => 100,
'L' => 50,
'X' => 10,
'V' => 5,
'I' => 1
);
// Convert the string to an array of roman values:
for ( $i = 0; $i < strlen ( $str ); $i ++)
if (isset( $roman [ strtoupper ( $str [ $i ])]))
$values [] = $roman [ strtoupper ( $str [ $i ])];
// Calculate the sum of that array:
$sum = 0;
while ( $current = current( $values ))
{
$next = next( $values );
$next > $current ? $sum += $next - $current + 0 * next( $values ) : $sum += $current ;
}
// Return the value:
return $sum ;
}
// echo roman2dec(IX);
?>
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希望本文所述对大家的php程序设计有所帮助。