|
|
|
|
Bookmark this on Delicious
Share on Facebook
 Slashdot It!
Digg bindec
Binary to decimal
(PHP 4, PHP 5)
Returns the decimal equivalent of the binary number represented by the binary_string argument. bindec() converts a binary number to an integer or, if needed for size reasons, float. ChangeLog
ExamplesExample 1139. bindec() example<?phpThe above example will output: 51
See Also
Related Examples ( Source code ) » bindec Examples ( Source code ) » decbin Examples ( Source code ) » bindec Code Examples / Notes » bindecda_he4datthe-gurusdotde
[Editor's Note: Numeric values starting with 0 are interpreted as octal (base eight) values. For example: 0101 is converts to 65 --zak@php.net] i was quite confused while werking with those bindec()/decbin() functions.. while echo decbin(bindec(1)); echo decbin(bindec(10)); echo decbin(bindec(101)); just worked like expected, echo decbin(bindec(010)); returns just 0 and for any reason echo decbin(bindec(010010010)); returns 101000 i dont think this is a bug (maybe theres some special reason 4 this?), but it took a certain time till i noticed that echo decbin(bindec("010010010")); works fine ... hope this helps ne1. gwbdome
i think a better method than the "shift-method" is my method ^^... here it comes: function convert2bin($string) { $finished=0; $base=1; if(preg_match("/[^0-9]/", $string)) { for($i=0; $string!=chr($i); $i++); $dec_nr=$i; } else $dec_nr=$string; while($dec_nr>$base) { $base=$base*2; if($base>$dec_nr) { $base=$base/2; break; } } while(!$finished) { if(($dec_nr-$base)>0) { $dec_nr=$dec_nr-$base; $bin_nr.=1; $base=$base/2; } elseif(($dec_nr-$base)<0) { $bin_nr.=0; $base=$base/2; } elseif(($dec_nr-$base)==0) { $bin_nr.=1; $finished=1; while($base>1) { $bin_nr.=0; $base=$base/2; } } } return $bin_nr; } ===================================================== if you want to reconvert it (from binary to string or integer) you can use this function: function reconvert($bin_nr) { $base=1; $dec_nr=0; $bin_nr=explode(",", preg_replace("/(.*),/", "$1", str_replace("1", "1,", str_replace("0", "0,", $bin_nr)))); for($i=1; $i<count($bin_nr); $i++) $base=$base*2; foreach($bin_nr as $key=>$bin_nr_bit) { if($bin_nr_bit==1) { $dec_nr+=$base; $base=$base/2; } if($bin_nr_bit==0) $base=$base/2; } return(array("string"=>chr($dec_nr), "int"=>$dec_nr)); } php
For converting larger-than-31-bit numbers: <?php function Bin2Dec($binstring) { for ($i=0;$i<strlen($binstring);$i++) { $decvalue += ((int) substr($binstring, strlen($binstring) - $i - 1, 1)) * pow(2, $i); } return $decvalue; } ?> 26-aug-2004 10:42
decbin('1001') is prefered as decbin(1001). Because on larger bit string, it may cause problem : decbin(100000000000000) return 3 else decbin('100000000000000') return 16384 juancri
> The special reason 4 this is: > (010) is an integer, left 0 is null, eg 010 = 10 > ('010') is a string, eg '010' = '010' In binary, just like with decimals, the left 0's are nulls. in Decimal: 010 = 10 in Binary: 010 = 10 too :o) > echo decbin(bindec(010010010)); > returns 101000 010010010 is a octal number. It's eq. to 2101256 (decimal). decbin(bindec(010010010)) is 101000 because 010010010 = 2101256. That's all =) martin
## calculate binary with "shift-method" ## <?php function dec2bin($decimal_code){ for($half=($decimal_code);$half>=1;$half=(floor($half))/2){ if(($half%2)!=0){ $y.=1; } else{ $y.=0; } } $calculated_bin=strrev($y); return $calculated_bin; } ?> ## example ## [bin] 123 = [dec] 1111011 e.g. 123/2 = 61,5 => 1 61/2 = 30,5 => 1 30/2 = 15 => 0 15/2 = 7,5 => 1 7/2 = 3,5 => 1 3/2 = 1,5 => 1 1/2 = 0,5 => 1 (0/2 = 0 finish) |
