<?php
function bc_is_even($int_str) {
if (0 < strlen($int_str)) {
return !((substr($int_str, -1)) % 2);
} else {
// error
return 0;
}
}
?>
bcmod
Description
string bcmod ( string left_operand, string modulus )Get the modulus of the left_operand using modulus.
add a note
User Contributed Notes
jmullan at visi dot com
25-Jul-2006 06:12
25-Jul-2006 06:12
cristianDOTzuddas]NOSPAM[gmailDOTcom
24-Jul-2005 06:45
24-Jul-2005 06:45
BC Math is really cool, but has only 10 functions. So we MUST write other BC functions and share the code.
Here is a simple even/odd number check.
<?
function bc_is_even($int_str) {
if (strlen($int_str)>0) {
if (bcmod($int_str, 2)==='0')
return true;
else
return false;
}
else // error
return 0;
}
?>
lauris at night dot lt
24-Dec-2003 12:04
24-Dec-2003 12:04
<?php
/**
* my_bcmod - get modulus (substitute for bcmod)
* string my_bcmod ( string left_operand, int modulus )
* left_operand can be really big, but be carefull with modulus :(
* by Andrius Baranauskas and Laurynas Butkus :) Vilnius, Lithuania
**/
function my_bcmod( $x, $y )
{
// how many numbers to take at once? carefull not to exceed (int)
$take = 5;
$mod = '';
do
{
$a = (int)$mod.substr( $x, 0, $take );
$x = substr( $x, $take );
$mod = $a % $y;
}
while ( strlen($x) );
return (int)$mod;
}
// example
echo my_bcmod( "7044060001970316212900", 150 );
?>
mackaye at iprimus dot com dot au
17-Sep-2003 01:28
17-Sep-2003 01:28
It is correct to use $i%2 to get even and odd program control
HOWEVER
using bit level operators is better, faster and more effecient
so
TO get odd and even $num&1 is much better
To NULL any element $element^$element is also much better
For New comers
these functions are based on the binary representation of variables in memory.
It so happens that an even number always has a
0 on the end, and an odd number always has a 1 on
the end
so
1010101 &
0000001
is true
timo at in-timo dot de
25-Jun-2003 09:15
25-Jun-2003 09:15
Check a 10-digit barcode with the Modulo11-ckecksum like this:
<?php
function modulo11 ($barcode) {
$sum = 0;
FOR ( $i=0; $i<=8; $i++ ) {
$add = $barcode{$i} * ($i+1);
$sum = $sum + $add;
}
$modulo = $sum % 11;
IF ( $modulo == 10 ) { $modulo = "X"; }
IF ( $barcode{9} == $modulo ) {
return true;
} ELSE {
return false;
}
}
?>
The function returns "true" if the barcode was read properly.